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  • 201. Grivickas, P.
    et al.
    Grivickas, V.
    Linnros, Jan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Galeckas, A.
    Fundamental band edge absorption in nominally undoped and doped 4H-SiC2007In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 101, no 12Article in journal (Refereed)
    Abstract [en]

    Fundamental band edge absorption is investigated in nominally undoped (n < 1014 cm(-3)) and heavily doped (n similar to 8 x 10(18) cm(-3)) 4H-SiC by a spectroscopy technique based on spatially and time-resolved free-carrier absorption. The spectra are extracted over a wide absorption range (0.02-500 cm(-1)) at temperatures from 75 to 450 K. The experimental results are supported by an indirect transition theory with a unique set of dominating momentum-conserving phonons, showing good correlation with earlier findings of differential absorption measurements at 2 K. Exciton binding energy of 30 +/- 10 meV is derived from fitting the data at 75 K. The detected polarization anisotropy of absorption with respect to c axis is shown to be consistent with the selection rules for the corresponding phonon branches. An analytical model related to constant degree of involved phonons describes well the obtained energy gap variation with temperature. Finally, doping induced band gap narrowing is characterized above the impurity-Mott transition and compared with theoretical calculations in the random phase approximation. The shape of the fundamental absorption edge at high carrier concentrations is discussed in terms of excitonic enhancement above the Mott transition, as recently detected in Si.

  • 202.
    Groleau, Romain
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Multipath Routing with Load Balancing in Wireless Ad Hoc Networks2005Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In recent years, routing research concerning wired networks has focused on minimizing the maximum utilization of the links which is equivalent to reducing the number of bottlenecks while supporting the same traffic demands. This can be achieved using multipath routing with load balancing instead of single path routing using of routing optimizers. However, in the domain of ad hoc networks multipath routing has not been investigated in depth. We would like to develop an analogy between wired and wireless networks, but before that we need to identify the major differences between these two in the case of multipath routing. First, in order to increase the network throughput, the multiple paths have to be independent so they don't share the same bottlenecks. Then, due to radio propagation properties the link capacity is not constant. So using the maximum utilization metric for wireless networks is not suitable. Based on the research done in wired networks, which has shown that using multiple paths with load balancing policies between sourcedestination pairs can minimize the maximum utilization of the links, we investigate if this is applicable to ad hoc networks.

    This paper proposes a multipath routing algorithm with a load balancing policy. The results obtained from an indoor 802.11g network highlight two major points. The maximum throughput is not achieved with multipath routing, but with single path routing. However, the results on the delivery ratio are encouraging, indeed we observe a real improvement thanks to our multipath routing algorithm.

  • 203.
    Gudmundsson, Valur
    et al.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Hellström, Per-Erik
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Zhang, Shi-Li
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Characterization of dopant segregated Schottky barrier source/drain contacts2009In: ULIS 2009: 10TH INTERNATIONAL CONFERENCE ON ULTIMATE INTEGRATION OF SILICON / [ed] Mantl S, Lemme M, Schubert J, Albrecht W, NEW YORK: IEEE , 2009, p. 73-76Conference paper (Refereed)
    Abstract [en]

    In this paper, the gate-voltage dependent source/drain (S/D) resistance (R-SD) in dopant segregated (DS) Schottky barrier (SB) junctions is examined by experiment and simulation. The focus is placed on fully depleted UTB-SOI MOSFETs featuring PtSi S/D with As-DS realized at low temperatures. When modeling SB-S/D with DS, it is challenging to determine if the performance enhancement observed is induced by a highly doped shallow layer in Si or by an interfacial dipole causing SB height lowering. The simulation reveals that the gate-voltage dependence of R-SD is stronger for the dipole effect. For the SB-MOSFETs with DS-S/D examined in this work, the simulation gives an excellent fit to the measured data when SBH lowering is combined with high concentration shallow doping.

  • 204.
    Gunnarsson, Mikael
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Truck-Trailer Wireless Connections2001Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Scania Infotronics is a subsidiary of Scania AB that works with IT-solutions for heavy vehicles. In one of Scania Infotronics’ projects a handheld computer is installed in a truck and connected to the vehicle’s data bus. From this data bus it is possible to collect a vast amount of data that is generated by the truck. The problem today is that the data bus does not reach into any trailers that are coupled to the truck, and no data can therefore be gathered from the trailers. A wireless link between the truck and the trailer would solve this problem. Possibly the unit installed in the trailer should be made portable in order for it to be easily moved between different trailers.

    This project will examine some of the technologies currently available that could be used to solve this. This will include studies of technologies such as DECT, BlueTooth. Some other technologies will be discarded in an early stage and others will be more thoroughly examined. During the implementation phase a prototype will be created for testing and evaluation.

    There has already been lots of work done as some of these wireless technologies have been around for a while and they are well standardized and widely deployed. What makes this project difficult is choosing the most suited technology for use in the very special environment that the truck and its trailer constitute. Furthermore the hardware and the software necessary are expected to raise interesting problems requiring new solutions.

  • 205.
    Gutti, Krishna
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Low cost secure network connectivity for a municipal organization2005Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Wireless Local Area Networks (WLANs) based on 802.11 technology were initially conceived with the aim of providing wireless connectivity to client devices in limited areas, such as office buildings, homes, etc. or in places where wires are too expensive to be placed. This ‘anywhere’ connectivity is said to have improved worker’s productivity by allowing one to work flexibly from various places besides one’s desk. Currently we are witnessing the growth of both public and private networks based on WLAN technology. Such hotspots are usually limited to the network owner’s premises such as her office, campus, etc. This limits the total coverage area of this network. It is often not economically feasible for a network access provider to install Access Points at all places that a network user might go. This has become a problem for many network access providers; a sensible solution would be to collectively address the problem by entering into roaming agreements as is already done by most Wide Area Wireless Network providers. Such operator specific roaming agreements can provide nearly continuous coverage over a much wider area such as an entire city. One of the goals of this project was to study potential cost effective technical solutions that provide WLAN access to City of Stockholm’s network based on 802.11 technologies; including evaluation from different technical aspects (e.g., capacity enhancements, improvements in handover latency, etc). Proper deployment and management strategies were also evaluated. Technologies permitting differentiated services for users, enabling provisioning of Voice over Wireless Local Area Network (VoWLAN) services and other interactive services were studied. Technologies for authentication, authorization and accounting were studied. Additionally technical means of providing secure access to the wireless network were investigated. Evaluation of architectures that allow inter-operator roaming were made.

    Today’s corporate users are increasingly mobile and there is a need to provide secure access to corporate data to these mobile users. The coverage offered by WLAN networks even with large roaming agreements would still have coverage gaps which can be reduced by relying on the 3G networks which are being widely deployed. Virtual Private Network technologies are successfully used for providing secure remote access to data and Mobile IP technology provides application persistence to mobile users even while switching between networks (e.g., WLAN to 3G). There is a need for them to co-exist in order to provide secure, mobile access to data. Such secure mobile access could also be provided without relying on the above, standardised solutions. A goal of this master’s thesis was to evaluate the technical solutions to enable such secure, mobile access to data. Current products were evaluated and a suggestion of suitable products for the City of Stockholm was given.

    The above solutions together would provide the City of Stockholm with secure wireless network connectivity[.]

  • 206.
    Gvozdic, Dejan
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Ekenberg, Ulf
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Strong enhancement of Rashba effect in strained p-type quantum wells2005In: Physics of Semiconductors, Pts A and B / [ed] Menendez, J; VanDeWalle, CG, MELVILLE: AMER INST PHYSICS , 2005, Vol. 772, p. 1423-1424Conference paper (Refereed)
    Abstract [en]

    One of the most studied spintronic devices is the spin transistor proposed by Datta and Das. The mechanism behind this transistor is the Rashba effect: The inversion asymmetry caused by the gate voltage gives rise to a spin splitting. We show that the relevant spin splitting in k-space is typically two orders of magnitude larger in unstrained p-type quantum wells compared to n-type quantum wells. We also show that further order-of-magnitude improvement can be obtained by utilizing the frequently ignored lattice-mismatch between GaAs and AlGaAs.

  • 207.
    Gvozdic, Dejan M.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Ekenberg, Ulf
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Investigation of the super-efficient Rashba effect by simulation of Shubnikov-de Haas oscillations in a two-dimensional hole gas2006In: Physica. E, Low-Dimensional systems and nanostructures, ISSN 1386-9477, E-ISSN 1873-1759, Vol. 34, no 02-jan, p. 377-380Article in journal (Refereed)
    Abstract [en]

    The Shubnikov-de Haas effect is frequently used for two-dimensional systems to determine individual subband populations, e.g. when the subbands are split by the Rashba effect. We have previously shown that the Rashba effect can give a wave vector splitting for holes that is up to three orders of magnitude larger than for electrons at the same electric field. To reach the optimum we have made a careful design of a modulation-doped quantum well with a top gate in which the negative differential Rashba effect is utilized. From the calculated hole Landau levels we determine the density of states at the Fermi energy and demonstrate a clear difference between the symmetric case without bias and the asymmetric case with a gate voltage of 100 meV, where the spin subband populations differ by a factor 3.

  • 208. Gvozdic, Dejan M.
    et al.
    Ekenberg, Ulf
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Rapid spin flip in a spin subband at an anticrossing region in a slightly asymmetric modulation-doped quantum well2008In: Physica. E, Low-Dimensional systems and nanostructures, ISSN 1386-9477, E-ISSN 1873-1759, Vol. 40, no 6, p. 2081-2083Article in journal (Refereed)
    Abstract [en]

    The spin splitting due to structure and bulk inversion asymmetry is calculated for electron subbands in wide slightly asymmetric InGaSb quantum wells. At anticrossings, rapid spin flips in two steps are found as the in-plane wave vector along the [1 1] direction is increased by 0.002 nm(-1). First the y-component and then the x-component is flipped. A change of bias of about 1 meV across the quantum well is sufficient move the Fermi level across the anticrossing region.

  • 209.
    Gvozdic, Dejan M.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schlachetzki, A
    Modulation response of V-groove quantum-wire lasers2005In: IEEE Journal of Quantum Electronics, ISSN 0018-9197, E-ISSN 1558-1713, Vol. 41, no 6, p. 842-847Article in journal (Refereed)
    Abstract [en]

    We analyze the modulation speed of an InGaAs-InP quantum-wire laser of a V-groove-shaped structure. The bandwidth is affected by the optical confinement Gamma, exhibiting a maximum at Gamma = 0.016. The maximum bandwidth for the intrinsic device is 20 GHz as a result of a calculation based on the experimentally obtained cross section of the device and including the nonparabolicity of the conduction and valence bands. We discuss the reduction of the bandwidth of the device itself by summarily considering the influence of the roll-off time and the cavity length as well as the nonlinear gain suppression.

  • 210. Gvozdić, D. M.
    et al.
    Ekenberg, Ulf
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Novel mechanism for rapid spin flip with increasing in-plane wave vector in slightly asymmetric modulation-doped quantum wells2008In: PROCEEDINGS OF THE 17TH INTERNATIONAL VACUUM CONGRESS/13TH INTERNATIONAL CONFERENCE ON SURFACE SCIENCE/INTERNATIONAL CONFERENCE ON NANOSCIENCE AND TECHNOLOGY, 2008, Vol. 100, no PART 5Conference paper (Refereed)
    Abstract [en]

    We calculate the electric-field-induced spin splittings in wide slightly asymmetric modulation-doped quantum wells. When spin subbands are anticrossing we demonstrate twostep spin flips as the in-plane wave vector along the [11] direction is increased by 0.002 nm-1. At the beginning of this interval the y-component flips, at the end the x-component. Simultaneously the energy separation stays roughly constant below 1-eV and the wave functions are interchanged. A bias change of about 1 meV is sufficient to move the Fermi level from below to above the anticrossing region.

  • 211.
    Gårdlund, Martin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    A Conceptual Model of Mobile Marketing for a Multinational Consumer Goods Company2005Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the last 10 years, mobile phones have gone from being an exclusive almost unnecessary high-tech device to being an everyday item, used by billions of people around the world. The technology evolution has changed phones from a suitcase sized mobile phone imitating its stationary counterpart, to a small communication device that can perform more than twenty different tasks and is usually less than half the size of the a traditional fixed phone.

    With this massive adoption of mobile phones come business opportunities. One of these opportunities is to make use of its potential as a large scale marketing communication channel. Marketing via the mobile networks, presents a large target audience that can be compared to broadcast media such as television and radio, but despite this can still be a personal channel and hence compared to direct mail or one-to-one marketing.

    Many, both successful and failed, mobile marketing schemes have been tried, but without any definite answers and no clear action plan. Considering that much of the success of Procter & Gamble can be attributed to the company’s skill in mass marketing, there is a need within the company to research the potential advantages and disadvantages of mobile marketing. This thesis explores whether or not mobile marketing is mature enough to permanently introduce it to the marketing mix of the company.

  • 212. Haase, A.
    et al.
    Schwarz, M.
    Wilzbach, M.
    Schmiedmayer, J.
    Liu, X.
    Brenner, K. -H
    Hessmo, Björn
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Horak, P.
    Microcavities on atom chips for single-atom detection2005Conference paper (Refereed)
  • 213.
    Hacklin, Fredrik August
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    A 3G Convergence Strategy for Mobile Business Middleware Solutions: Applications and Implications2001Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Mobile business solutions are one of the most attractive market segments of mobile information services. The third generation of mobile communication systems (3G) will be a significant step forward in the convergence of telecommunications and datacommunications industries. More specifically, the convergence of mobile technologies and the Internet allows compelling possibilities for future applications and solutions. However, most current mobile businesses and mobile application and solution providers are rather contributing to the process of convergence; many current ideas and solutions are based on the restrictions of existing mobile networks combined with Internet-based services. In the future, when mobile networks and the Internet have merged, it will no longer be possible to create revenue with these types of solutions.

    One concrete solution is the mobile middleware concept, bridging the mobile technologies and Internet world. This Master’s thesis studies the middleware concept for providing business applications in the light of 3G, making strategic recommendations to a provider of these kinds of services. A comprehensive discussion about the developments after 3G is introduced. Alternative solutions are presented and some strategic implications are introduced. The implications are motivated by an industry survey, carried out within this project. The topic of over-the-air data synchronization is discussed as an example for interim middleware. Mobile computing file system issues are seen as an interesting opportunity for business applications. The possibility of remote desktop screen access is studied, and measurements proving its feasability for hosted wireless application service provision are made. Emerging mobile Java technologies are discussed as an efficient platform for providing ubiquitous, device independent end-to-end solutions. As one of the recommended strategies, this thesis introduces the concept of hybrid thickness client applications as a feasible solution for migrating from current middleware solutions to an (uncertain) future of native, thick terminal applications, within a scope of two years. Based on this concept, a prototype for a 3G smartphone application was developed as an example. A set of possible strategic scenarios is presented and discussed. This thesis also discusses operator differentiation and business solutions in an all-IP based world.

    3G networks and handset devices will introduce a large number of new applications and business opportunities, but such a change will also introduce new challenges and risks. The migration challenge is being illustrated in the case of Smartner, a mobile middleware solution provider focusing on business applications. As shown by this case, compared to current enabling solutions, a major shift in technologies is seen as needed, in order to maintain long-term success.

  • 214.
    Hagsand, Olof
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Hidell, Markus
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Sjödin, Peter
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Design and implementation of a distributed router2005In: 2005 IEEE International Symposium on Signal Processing and Information Technology (ISSPIT), Vols 1 and 2, 2005, p. 227-232Conference paper (Refereed)
    Abstract [en]

    The requirements on 1P routers are increasing for every new generation of designs. The driving forces are growing traffic volumes and demands for new services. We argue that a decentralized modular system design would improve the scalability. flexibility, and reliability of future routers. We have designed and implemented such a distributed router. based on physical separation between different junctional modules for control and forwarding plane operations. This paper presents the design and implementation, focusing on the internal communication protocols and implementation aspects of the control plane.

  • 215. Haider, J. M.
    et al.
    Kramer, Elissa L.
    New York University, Department of Radiology.
    Maguire Jr., Gerald Q.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Millan, Evelyn
    New York University.
    Noz, Marilyn E.
    New York University, Department of Radiology.
    Orbach, D. B.
    Zeleznik, Michael P.
    Saya Systems Inc., Salt Lake City, UT, USA.
    Problems with two automatic methods for SPECT-SPECT and SPECT-MRI Volume Matching2002In: Medical physics (Lancaster), ISSN 0094-2405, Vol. 29, no 8, p. 1944-Article in journal (Refereed)
  • 216. Hakkarainen, T.
    et al.
    Setala, T.
    Friberg, Ari. T.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Near-field imaging of point dipole with silver superlens2010In: Applied physics. B, Lasers and optics (Print), ISSN 0946-2171, E-ISSN 1432-0649, Vol. 101, no 4, p. 731-734Article in journal (Refereed)
    Abstract [en]

    Making use of exact and quasistatic expressions for the field in near-field imaging of a point dipole by a thin silver slab, we calculate the point-spread function and the associated image resolution. We show that the resolution, which depends on the silver slab thickness and the dipole orientation, generally is better than the conventional diffraction limit and can be as high as lambda/8. The results substantially agree with recent theoretical and experimental studies on 2D objects.

  • 217.
    Hallén, Anders.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Suchodolskis, Arturas
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Österman, John
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Abtin, L.
    Linnarsson, Margareta K.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Annealing of Al implanted 4H silicon carbide2006In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T126, p. 37-40Article in journal (Refereed)
    Abstract [en]

    Al ions were implanted with multiple energies up to 250 keV at elevated temperatures in n-type 4H SiC epitaxial layers to reach a surface concentration of 1 x 10(20) cm(-3). These samples were then annealed at temperatures between 1500 and 1950 degrees C. A similar 4H SiC epitaxial sample was implanted by MeV Al ions to lower doses and annealed only at 200 and 400 degrees C. After annealing, cross-sections of the samples were characterized by scanning spreading resistance microscopy (SSRM). The results show that the resistivity of high-dose Al implanted samples has not reached a saturated value, even after annealing at the highest temperature. For the MeV Al implanted sample, the activation of Al has not yet started, but a substantial annealing of the implantation induced damage can be seen from the SSRM depth profiles.

  • 218.
    Hammar, Mattias
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    von Würtemberg, Rickard Marcks
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Sundgren, Petrus
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Berggren, Jesper
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Larsson, A.
    Söderberg, E.
    Modh, P.
    Gustavsson, J.
    Ghisoni, M.
    Chitica, N.
    1.3-mu m InGaAs vertical-cavity surface-emitting lasers2005In: 2005 IEEE LEOS Annual Meeting Conference Proceedings (LEOS), 2005, p. 396-397Conference paper (Refereed)
    Abstract [en]

    We report on the fabrication and performance of N-free InGaAs/GaAs 1.3-mu m range vertical-cavity surface-emitting lasers (VCSELs). Using optimized quantum-well (QW) growth conditions in combination with negative gain-cavity tuning, high-performance VCSELs with emission wavelength up to 1300 nm are realized. The performance figures include mA-range threshold currents, mW-range singlemode output power, continuous-wave operation up to 140 degrees C and 10 Gbit/s data transmission.

  • 219.
    Hans, Mat
    et al.
    HP.
    Hoover, Christopher
    HP.
    Maguire Jr., Gerald Q.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Smith, Mark T.
    HP.
    Badge 4 Embedded Development Kit: Bastille Day Release2002Report (Other academic)
  • 220.
    Haralson, Erik
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Suvar, E.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Malm, B. Gunnar
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Radamson, Henry
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wang, Yong-Bin
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    NiSi integration in a non-selective base SiGeCHBT process2005In: Materials Science in Semiconductor Processing, ISSN 1369-8001, E-ISSN 1873-4081, Vol. 8, no 03-jan, p. 245-248Article in journal (Refereed)
    Abstract [en]

    A self-aligned nickel silicide (salicide) process is integrated into a non-selective base SiGeC HBT process. The device features a unique, fully silicided base region that grows laterally under the emitter pedestal. This Ni(SiGe) formed in this base region was found to have a resistivity of 23-24 muOmega cm. A difference in the silicide thickness between the boron-doped SiGeC extrinsic base region and the in situ phosphorous-doped emitter region is observed and further analyzed and confirmed with a blanket wafer silicide study. The silicided device exhibited a current gain of 64 and HF device performance of 39 and 32 GHz for f(t) and f(MAX), respectively.

  • 221.
    Haridi, Seif
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Ghodsi, Ali
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    A Framework for Structured Peer-to-Peer Overlay Networks2005In: GLOBAL COMPUTING / [ed] Priami, C; Quaglia, P, 2005, p. 223-249Conference paper (Refereed)
    Abstract [en]

    Structured peer-to-peer overlay networks have recently emerged as good candidate infrastructure for building novel large-scale and robust Internet applications in which participating peers share computing resources as equals. In the past three year, various structured peer-to-peer overlay networks have been proposed, and probably more are to come. We present a framework for understanding, analyzing and designing structured peer-to-peer overlay networks. The main objective of the paper is to provide practical guidelines for the design of structured overlay networks by identifying a fundamental element in the construction of overlay networks: the embedding of k–ary trees. Then, a number of effective techniques for maintaining these overlay networks are discussed. The proposed framework has been effective in the development of the DKS system, whose preliminary design appears in [2].

  • 222. Hassinen, T.
    et al.
    Tervo, J.
    Friberg, Ari T.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Cross-spectral purity of the Stokes parameters2011In: Applied physics. B, Lasers and optics (Print), ISSN 0946-2171, E-ISSN 1432-0649, Vol. 105, no 2, p. 305-308Article in journal (Refereed)
    Abstract [en]

    We extend the concept of cross-spectral purity from the spectral density to the polarization properties of electromagnetic fields by considering the polarization Stokes parameters. We show that purity conditions similar to those in the case of electromagnetic cross-spectral purity can be derived for all the Stokes parameters. Furthermore, we introduce a situation of strict cross-spectral purity which leads to the equality of the degrees of coherence for electromagnetic fields in the space-time and space-frequency domains.

  • 223.
    Havelka, Dragan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Thread-based mobility for a distributed dataflow language2005Licentiate thesis, monograph (Other scientific)
    Abstract [en]

    Strong mobility enables migration of entire computations combining code, data, and execution state (such as stack and program counter) between sites of computation. This is in contrast to weak mobility were migration is confined to just code and data. Strong mobility is essential for many applications where reconstruction of execution states is either difficult or even impossible. Typical application areas are load balancing, reduction of network latency and traffic, and resource-related migration, just to name a few.

    This thesis presents a model, programming abstractions, an implementation, and an evaluation of thread-based strong mobility. The model extends a distributed programming model based on automatic synchronization via dataflow variables. The programming abstractions capture various migration scenarios. These scenarios differ in how migration source and destination relate to the site initiating migration. The implementation is based on replication of concurrent lightweight threads between sites controlled by migration managers. The model is implemented in the Mozart programming system. The first version is complete and a work concerning resource rebinding is still in progress.

  • 224.
    Havelka, Dragan
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schulte, Christian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Brand, P
    Haridi, Seif
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Thread-based mobility in Oz2005In: MULTIPARADIGM PROGRAMMING IN MOZART/OZ / [ed] Roy, PV, BERLIN: SPRINGER-VERLAG BERLIN , 2005, Vol. 3389, p. 137-148Conference paper (Refereed)
    Abstract [en]

    Strong mobility enables migration of entire computations combining code, data, and execution state (such as stack and program counter) between sites of computation. This is in contrast to weak mobility where migration is confined to just code and data. Strong mobility is essential for many applications where reconstruction of execution states is either difficult or even impossible: load balancing, reduction of network latency and traffic, and resource-related migration, just to name a few. This paper presents a model, programming abstractions, implementation, and evaluation of thread-based strong mobility. The model extends and takes advantage of a distributed programming model based on automatic synchronization through dataflow variables. It comes as a natural extension of dataflow computing which carefully separates issues concerning distribution and mobility. The programming abstractions capture various migration scenarios which differ in how the source and destination site relate to the site initiating migration. The implementation is based on replicating concurrent lightweight threads between sites controlled by migration managers.

  • 225.
    Hedberg, Daniel
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Network Processor based Exchange Terminal: Implementation and evaluation2002Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    When communication nodes are connected to different networks, different kinds of Exchange Terminals (ETs) i.e., line card, are used. The different media we consider here have a bit rate between 1.5Mbps to 622Mbps and use protocols such as ATM or IP. In order to minimize the number of different types of ET boards, it is interesting to study the possibility of using Network Processors (NP) to build a generic ET that is able to handle several link layer and network layer protocols and operate at a wide variety of bit rates.

    This report investigates the potential of implementing an ET board using a one-chip or twochip solution using an Intel Network Processor (NP). The design is described in detail including a performance analysis of the different modules (microblocks) used. The report also provides an evaluation of the IXP2400 network processor and contrasts it to some other network processors. The detailed performance evaluation is based on a simulator of the IXP2400, which is part of Intel's Software Development Kit (SDK) version 3.0. In addition, I have investigated: the memory bus bandwidth, memory access latencies, and compared Ccompiler against hand-written microcode. These tests were based on using an application for this ET board, which I have implemented.

    It proved to be difficult to fit all the required functions into a single chip solution. The result is either one must wait for the next generation of this chip or one has to use a two-chip solution. In addition, the software development environment used in the project was only a pre-release, and not all services worked as promised. However, a clear result is that implementing an ET board, supporting the commonly desired functions, using a Network Processor is both feasible and straightforward.

  • 226.
    Hellström, Per-Erik
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Edholm, J.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Olsen, S.
    O'Neill, A.
    Lyutovich, K.
    Oehme, M.
    Kasper, E.
    Strained-Si NMOSFETs on thin 200 nm virtual substrates2005Conference paper (Refereed)
  • 227. Hesselbom, Hjalmar
    et al.
    Norberg, Gunnar
    Dejanovic, Slavko
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Very High Density Interconnect Elastomer Chip Sockets2006In: IEEE Transactions on Advanced Packaging, ISSN 1521-3323, E-ISSN 1557-9980, Vol. 29, no 2, p. 202-210Article in journal (Refereed)
    Abstract [en]

    The integration of more and more functionality into smaller and smaller form factor electronic products, drives the need for denser chip to substrate interconnect systems. As the number of I/O pins increases, the use of area array chips or packages becomes inevitable. Metal patterned elastomer chip sockets have now been improved to work with contact densities as high as 80000 contacts/cm(2) corresponding to a pitch of 36 mu m. Sockets with 10000 contacts and a 72-mu m pitch have survived more than 400 cycles in air-to-air thermal cycling chambers as well as freezing shocks caused by dipping into liquid nitrogen. Although the daisy chain test circuits breaks for temperatures lower than -50 degrees C and higher than 90 degrees C, they always return to the initial resistance values when entering the normal temperature range. The combination of a gold-to-gold contact interface and the elastic features of the contact bumps makes this socket an ideal compliance layer between bare chips and different types of carrier substrates, reducing the problems caused by thermomechanical mismatch between the substrate and the chip. Bad dies can easily be replaced, since the chip is not soldered or glued to the socket. The size and the possibility to control the geometry of the contacts provides means to maintain a good high-frequency characteristic impedance matching all the way to the chip pad.

  • 228.
    Heydari, Heydari
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Björk, Gunnar
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Entanglement measure for pure M ⊗ N bipartite quantum states2005In: Optika i Spektroskopiya, ISSN 0030-4034, Vol. 99, no 3, p. 398-404Article in journal (Refereed)
    Abstract [en]

    We propose an entanglement measure for pure M ⊗N bipartite quantum states. We obtain the measure by generalizing the equivalent measure for a 2 ⊗ 2 system, via a 2 ⊗ 3 system, to the general bipartite case. The measure emphasizes the role Bell states have, both for forming the measure, and for experimentally measuring the entanglement. The form of the measure is similar to generalized concurrence. In the case of 2 ⊗ 3 systems, we prove that our measure, that is directly measurable, equals the concurrence. It is also shown that in order to measure the entanglement, it is sufficient to measure the projections of the state onto a maximum of M(M - 1)N(N - 1)/2 Bell states.

  • 229.
    Heydari, Hoshang
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Björk, Gunnar
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Entanglement measure for pure M circle times N bipartite quantum states2005In: Optics and Spectroscopy, ISSN 0030-400X, E-ISSN 1562-6911, Vol. 99, no 3, p. 379-385Article in journal (Refereed)
    Abstract [en]

    We propose an entanglement measure for pure M circle times N bipartite quantum states. We obtain the measure by generalizing the equivalent measure for a 2 circle times 2 system, via a 2 circle times 3 system, to the general bipartite case. The measure emphasizes the role Bell states have, both for forming the measure and for experimentally measuring the entanglement. The form of the measure is similar to the generalized concurrence. In the case of 2 circle times 3 systems, we prove that our measure, which is directly measurable, equals the concurrence. It is also shown that, in order to measure the entanglement, it is sufficient to measure the projections of the state onto a maximum of M(M-1)N(N-1)/2 Bell states.

  • 230.
    Heydari, Hoshang
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Björk, Gunnar
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Entanglement tensor for a general pure multipartite quantum state2005In: Quantum information & computation, ISSN 1533-7146, Vol. 5, no 2, p. 146-155Article in journal (Refereed)
    Abstract [en]

    We propose an entanglement tensor to quantitatively compute the entanglement of a general pure multipartite quantum state. We compare the ensuing tensor with the concurrence for bipartite state and apply the tensor measure to some interesting examples of entangled three-qubit and four-qubit states. It is shown that in defining the degree of entanglement of a multi-partite state, one needs to make assumptions about the willingness of the parties to cooperate. For such states our tensor becomes a measure of generalized entanglement of assistance. We also discuss the degree of entanglement and the concurrence of assistance of two generic multi-qubit states.

  • 231.
    Hidell, Markus
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Sjödin, Peter
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Hagsand, Olof
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Control and forwarding plane interaction in distributed routers2005In: NETWORKING 2005: NETWORKING TECHNOLOGIES, SERVICES, AND PROTOCOLS; PERFORMANCE OF COMPUTER AND COMMUNICATION NETWORKS; MOBILE AND WIRELESS COMMUNICATIONS SYSTEMS / [ed] Boutaba, R; Almeroth, K; Puigjaner, R; Shen, S; Black, JP, 2005, Vol. 3462, p. 1339-1342Conference paper (Refereed)
    Abstract [en]

    The requirements on IP routers continue to increase, both from the control plane and the forwarding plane perspectives. To improve scalability, flexibility, and availability new ways to build future routers need to be investigated. This paper suggests a decentralized, modular system design for routers, based on control elements for functionalities like routing, and forwarding elements for packet processing. Further, we present measurements on the distribution of large routing tables in an experimental platform consisting of one control element and up to 16 forwarding elements.

  • 232. Hillmer, H.
    et al.
    Tarraf, A.
    Riemenschneider, F.
    Irmer, S.
    Halbritter, H.
    Daleiden, J.
    Römer, F.
    Prott, C.
    Ataro, E.
    Hasse, A.
    Strassner, Martin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. CNRS-LPN, France.
    Hansmann, S.
    Meissner, P.
    Wide continuously tunable 1.55 μm vertical air-cavity wavelength selective elements for filters and VCSELs using micromachined actuation2005In: Opto-Ireland 2005: Optoelectronics, Photonic Devices, and Optical Networks, SPIE - International Society for Optical Engineering, 2005, p. 14-28Conference paper (Refereed)
    Abstract [en]

    Tailored scaling allows the effectiveness of physical effects and mechanical stability to be enhanced. This is shown for micromachined 1.55μm vertical-resonator-based filters and VCSELs, capable of wide, continuous, and kink-free tuning by a single control parameter. Tuning is achieved by mechanically actuating one or several membranes in a vertical air-gap resonator including two highly reflective DBR mirrors. Electrostatically actuatable single-chip filters including InP/air-gap DBR's (3.5 periods) reveal a continuous tuning up to 14% of the absolute wavelength. Varying a reverse voltage (U=0 .. -3.2V) between the membranes (almost flat in the unactuated condition) a tuning range up to 142nm was obtained. Varying a reverse voltage (U=0 .. -28V) between the membranes (strained and curved in the unactuated condition) a tuning range up to 221nm was obtained. Optically pumped and continuously tunable 1.55μm VCSELs show 26nm spectral tuning range, 400μW maximum output power, and 57dBm SMSR. This two-chip VCSEL has a movable top mirror membrane, which is precisely designed to obtain a specific air-gap length and a tailored radius of curvature in order to efficiently support the fundamental optical mode of the plane-concave resonator. The curved top mirror DBR membrane consists of periodically alternating differently stressed silicon nitride and silicon dioxide multilayers. The lower InP-based part consists of the InP/GaInAsP bottom DBR and the GaInAsP active region.

  • 233.
    Hjelm, Mats
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. Department of Information Technology and Media, Mid-Sweden University, Sweden .
    Nilsson, H. E.
    Martinez, A.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Critical evaluation of scattering models within the full band monte carlo simulation framework2005In: Recent Advances in Multidisciplinary Applied Physics: Proceedings of the First International Meeting on Applied Physics (APHYS-2003) October 13-18th 2003, Badajoz, Spain, Elsevier, 2005, p. 305-311Conference paper (Refereed)
    Abstract [en]

    The full band Monte Carlo (MC) simulation framework is regarded as the most accurate method available to study high-field carrier transport in semiconductors. Its potential has been demonstrated in a large number of studies over the years. In this work we focus on how the quantum mechanical uncertainty at high scattering rates affects the validity of Fermi’s Golden Rule, which traditionally is the basis for the scattering handling in the MC method. Considering the uncertainty is important in for instance silicon carbide, which at moderate energies exhibits a scattering rate exceeding 1014 s- 1. The expression for time-dependent scattering rate is presented together with calculated rates for some initial states with acoustic as well as polar-optical phonon interaction. A first-order time-dependent algorithm for handling of scattering events in MC simulators is proposed.

  • 234.
    Holmlund, Erik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    A comparative study of two different network basedIP Virtual Private Network solutions2003Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Network based (layer 3) IP VPNs is a growing service and Skanova has a solution today which has received a lot of customer attention. The service is called VPN Flex and offers the customers secure communication between their different offices while supporting different traffic classes with a guaranteed maximum delay, jitter, and packet loss. VPN Flex has been a success so far in terms of the number of customers that have signed up for it in the short time it has been on the market. VPN Flex is realized over an IP network on Skanova's ATM backbone.

    Meanwhile Multi Protocol Label Switching (MPLS) has attracted a lot of attention and is considered to have a lot of nice features; the most import being the ability to provide layer 2 and layer 3 IP VPNs. The MPLS solution for providing network based layer 3 IP VPNs is described in RFC 2547, also called BGP/MPLS VPNs. It has become the de-facto standard for providing network based layer 3 IP VPNs. Skanova's VPN Flex service is provided by a partly Nortel proprietary solution using IP tunneling instead of MPLS tunneling which is used in RFC 2547.

    The purpose of this paper is to evaluate which network (i.e. link layer technology; specifically a frame based or a cell based media) and which network based IP VPN solution is most suitable to provide a network based layer 3 IP VPN service that supports different traffic classes so that Skanova's customers can use this VPN service to send best effort traffic, mission critical applications, IP Telephony, and Video Conferencing services between their different offices using a single layer 3 VPN solution.

    In my evaluation I have looked at the technology behind the VPN solution, the ability to provide delay, jitter, and packet loss guarantees as well as what it costs to produce the service along with the security and expected reliability. The purpose of having a master’s thesis student looking at this problem is that I would be objective and not have any predetermined conclusions.

    The result of the study is that the two different network based VPN solutions are not different with regard to the service they provide for the customers. However, there are some differences that affect the operator deploying and running the service. RFC 2547 is a more flexible solution with less manual configuration and better support for Inter-AS VPNs. It is possible to realize an RFC 2547 solution in either an ATM network or an IP network and the services will be implemented in much the same way. Both solutions could use Label Distribution Protocol (LDP) signaling and EXP Inferred PHB Scheduling Class LSPs (ELSPs), realizing traffic classes using the MPLS EXP bits. Which network to base the solution on, is a matter of QoS support, costs, and security. The ATM network today has better QoS support (such as more transmission queues and efficient schedulers). However, at the link speeds used in today’s backbones the fixed size cell of ATM is not a reason to use the ATM network instead of a frame based IP network.

    The cost of using Packet Over Sonet (POS) and ATM is the same. However, using Ethernet the port cost is less than half of either POS or ATM, which favors using an IP network in the A comparative study of two different network based IP Virtual Private Network solutions future. The security of a network based layer 3 IP VPN is mostly in the hands of the operator configuring the service and the network. Thus with regard to security, I do not believe there is a difference when realizing the network based IP VPN service in a public or private IP network. However, a network based IP VPN realized in a public IP network might pose a sales problem because many customers are worried about the security and availability of such a network.

    RFC 2547 and MPLS seem to be the way to go in the future, but my recommendation is to make the transition slowly thereby minimizing Capital Expenditures (CAPEX). This is especially true since the current network based IP VPN service has been so well received. Whether Skanova should introduce MPLS and RFC 2547 in the IP network or the ATM network is very much dependent on their future strategy. I believe that both the IP network and the ATM network can support a service such as VPN Flex. Also, the way that MPLS will be used with regard to the VPN Flex service is the same.

  • 235.
    Holmstrom, Petter
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Thylen, Lars
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Bratkovsky, Alexander
    Composite metal/quantum-dot nanoparticle-array waveguides with compensated loss2010In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 97, no 7, p. 073110-Article in journal (Refereed)
    Abstract [en]

    We calculate the dispersion properties of waveguides composed of near-field-coupled arrays of metal-clad quantum dots (QDs). The high optical loss incurred by operating the metal shells close to resonance is mitigated by using optical gain in the QDs. A condition for achieving loss compensated operation is given based on realistic material parameters and neglecting inhomogeneous broadening. (C) 2010 American Institute of Physics. [doi:10.1063/1.3467845]

  • 236.
    Holmström, Petter
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Jänes, Peter
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Ekenberg, Ulf
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Thylen, Lars
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Efficient electroabsorption for mid-infrared wavelengths using intersubband transitions2008In: PROCEEDINGS OF THE 17TH INTERNATIONAL VACUUM CONGRESS/13TH INTERNATIONAL CONFERENCE ON SURFACE SCIENCE/INTERNATIONAL CONFERENCE ON NANOSCIENCE AND TECHNOLOGY / [ed] Johansson LSO, Andersen JN, Gothelid M, Helmersson U, Montelius L, Rubel M, Setina J, Wernersson LE, Bristol: IOP PUBLISHING LTD , 2008, Vol. 100Conference paper (Refereed)
    Abstract [en]

    We have demonstrated efficient intersubband (IS) electroabsorption in InGaAs/InAlGaAs/InAlAs step quantum wells grown by metal-organic vapor phase epitaxy (MOVPE). An absorption modulation of 2300 cm(-1) at lambda=5.7 mu m due to Stark shift of the IS resonance was achieved with a low applied voltage swing of +/-0.5 V in a multipass waveguide structure. Two useful wavelength ranges of lambda approximate to 5.4-5.8 mu m and 6.3-6.6 mu m were obtained by considering the two flanks of the IS resonance. Based on the experimental results it is estimated that an electroabsorption modulator with a low peak-to-peak voltage of V-PP = 0.9 V can yield a modulation speed of f(3dB) = 120 GHz with the present material by using a strongly confining surface plasmon waveguide of 30 mu m length.

  • 237. Huang, Daming
    et al.
    Liu, Wei
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Liu, Zhiying
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Liao, C. C.
    Zhang, Li-Fei
    Gan, Zhenghao
    Wong, Waisum
    Li, Ming-Fu
    A Modified Charge-Pumping Method for the Characterization of Interface-Trap Generation in MOSFETs2009In: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 56, no 2, p. 267-274Article in journal (Refereed)
    Abstract [en]

    A novel recovery-free interface-trap measurement method is presented in detail. This method is the modification of the conventional charge pumping (CP) by extending the pulse low level to the stress-bias and minimizing the pulse high-level duty cycle to suppress the recovery effect. The method is applied to study the negative-bias temperature instability in p-MOSFETs. As compared with the conventional CP, a much larger interface-trap generation under stress is observed by the new method. A power law time dependence (similar to t(n)) of interface-trap generation is observed. The index n. is less than that derived from conventional CP and increases with temperature, demonstrating a dispersive process involved in the trap generation dynamics.

  • 238.
    Hållstedt, Julius.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Hellström, Per-Erik
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Radamson, Henry H.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Sidewall transfer lithography for reliable fabrication of nanowires and deca-nanometer MOSFETs2008In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 517, no 1, p. 117-120Article in journal (Refereed)
    Abstract [en]

    Today MOSFET devices are approaching gate lengths on the order of 10 nm. This sets extreme demands on gate patterning technique. This paper describes a side wall transfer lithography technique to pattern decananomeer MOSFETs or nanowires. A correlated line edge roughness leading to a very low line width roughness was demonstrated for the patterned gates. Moreover, the technology was shown to be robust and reproducible with high yield and uniformity suitable for mass fabrication. Finally, integration of the sidewall transfer lithography was performed in various novel MOSFET devices.

  • 239.
    Hållstedt, Julius
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Parent, A.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Radamson, Henry
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Incorporation of boron in SiGe(C) epitaxial layers grown by reduced pressure chemical vapor deposition2005In: Materials Science in Semiconductor Processing, ISSN 1369-8001, E-ISSN 1873-4081, Vol. 8, no 03-jan, p. 97-101Article in journal (Refereed)
    Abstract [en]

    In this paper the strain and electrical properties of epitaxial in situ B-doped (10(18)-10(21) cm(-3)) SiGeC layers (23, 28% Ge and 0, 0.5% C) has been investigated. The growth rate was shown to have a significant increase at 3 x 10(-2) mTorr diborane partial pressure. This point coincides with an enhancement in boron incorporation, which was explained by the strain compensation effect of boron in the highly strained SiGeC layers. In these samples, the total Ge and C content was shown to remain constant with increasing diborane partial pressure. The substitutional/active dopant concentration in SiGe layers was obtained by high-resolution X-ray diffraction by measuring the strain compensation effect of boron. The interaction between C and B in SiGe matrix was also investigated. This was compared with the active dopant concentration obtained from Hall measurements in order to achieve a Hall scattering factor of 0.3-0.7 for dopant concentrations between 3 x 10(18) and 5 x 10(21) cm(-3). The resistivity values of these layers were in the range 2 x 10(-2) -4 x 10(-4) Omega cm. Finally, it was shown that boron atoms in SiGeC layers locate preferably at substitutional sites in contrary to carbon atoms at both substitutional and interstitial sites.

  • 240.
    Hållstedt, Julius
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    von Haartman, Martin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Hellström, Per-Erik
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Radamson, Henry
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Noise and mobility characteristics of bulk and fully depleted SOI pMOSFETs using Si or SiGe channels2006In: ECS Transactions, ISSN 1938-5862, E-ISSN 1938-6737, Vol. 3, no 7, p. 67-72Article in journal (Refereed)
    Abstract [en]

    State of the art bulk and fully depleted SOI Si and SiGe channel pMOSFET devices with gate lengths ranging from 0.1 to 200 μm were fabricated and analyzed in terms of drain current drivability, mobility and noise performance. In general the SOI devices demonstrated superior mobility and significantly reduced I/f noise compared to bulk devices maintaining a well controlled short channel effects due to the ultra thin body.

  • 241.
    Hållstedt, Julius
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    von Haartman, Martin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Hellström, Per-Erik
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Radamson, Henry
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Hole mobility in ultrathin body SOI pMOSFETs with SiGe or SiGeC channels2006In: IEEE Electron Device Letters, ISSN 0741-3106, E-ISSN 1558-0563, Vol. 27, no 6, p. 466-468Article in journal (Refereed)
    Abstract [en]

    The hole mobilities of SiGe and SiGeC channel pMOSFETs fabricated on ultrathin silicon-on-insulator substrates are investigated and compared with reference Si channel devices. The total thickness of the fully depleted Si/SiGe(C)/Si body structure is similar to 25 nm. All devices demonstrated a near ideal subthreshold behavior, and the drive current and mobility were increased with more than 60% for SiGe and SiGeC channels. When comparing SIMOX and UNIBOND substrates, no significant difference could be detected.

  • 242.
    Immonen, Mia
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    SIGTRAN: Signaling over IP -- a step closer to an all-IP network2005Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The mass popularization of telecommunication services in recent years have resulted in a heavily loaded signaling network. The Signaling System number 7 (SS7) is used in fixed and wireless networks and is needed for call control and services such as caller ID, roaming, and for sending SMS. The traditional SS7 networks are expensive to lease and to expand, hence a new suite of protocols have been designed to carry signaling messages over IP. This suite contains a transport protocol called Stream Control Transmission Protocol (SCTP) and various user adaptation layer protocols such as M2PA, M2UA, M3UA, and SUA. To transport the highly loss and delay sensitive signaling messages over IP, it is mandatory that the transport protocol meets the high performance requirements of SS7. Not before the IP-solution has been tested in detail, will it replace significant parts of the national telephone network.

    In this thesis, the failover duration in the case of link failure was tested using the feature of SCTP called multi-homing. The results suggest that carrying SS7 signaling traffic over IP is possible, since the failover duration does not exceed the required limit.

  • 243. Intarasiri, S.
    et al.
    Dangtip, S.
    Hallén, Anders.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Jensen, J.
    Yu, L. D.
    Possnert, G.
    Singkarat, S.
    Activation energy of the growth of ion-beam-synthesized nano-crystalline 3C-SiC2007In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 257, p. 195-198Article in journal (Refereed)
    Abstract [en]

    In this experiment, carbon ions at 40 keV were implanted into (10 0) high-purity p-type silicon wafers at 400 degrees C to a fluence of 6.5 x 10(17) ions/cm(2). Subsequent thermal annealing of the implanted samples was performed in a vacuum furnace at 800-1000 degrees C. Glancing incidence X-ray diffraction (GIXRD) was used to characterize the crystalline quality and estimate the grain size of nano-crystalline 3C-SiC. Activation energy for the growth of 3C-SiC was evaluated following the annealing behaviour of the GIXRD-characteristic 3C-SiC (111) peaks. It was found that the 3C-SiC was directly formed during ion implantation at this substrate temperature and the activation energy of the process was about 0.05 eV. Such a low energy was explained in terms of ion beam induced precipitate formation.

  • 244. Intarasiri, S.
    et al.
    Hallén, Anders.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Kamwanna, T.
    Yu, L. D.
    Possnert, G.
    Singkarat, S.
    Characterization of the crystalline quality of beta-SiC formed by ion beam synthesis2006In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 249, p. 851-855Article in journal (Refereed)
    Abstract [en]

    The ion beam synthesis (IBS) technique is applied to form crystalline silicon carbide (SiC) for future optoelectronics applications. Carbon ions at 80 and 40 keV were implanted into (100) high-purity p-type silicon wafers at room temperature and 400 degrees C, respectively, to doses in excess of 10(17) ions/cm(2). Subsequent thermal annealing of the implanted samples was performed in a vacuum furnace at temperatures of 800, 900 and 1000 degrees C, respectively. Elastic recoil detection analysis was used to investigate depth distributions of the implanted ions and infrared transmittance (IR) measurement was used to characterize formation of SiC in the implanted Si substrate. Complementary to IR, Raman scattering measurements were also carried out. Levels of the residual damage distribution of the samples annealed at different temperatures were compared with that of the as-implanted one by Rutherford backscattering spectrometry (RBS) in the channeling mode. The results show that C-ion implantation at the elevated temperature, followed by high-temperature annealing, enhances the synthesis of crystalline SiC.

  • 245. Intarasiri, S.
    et al.
    Hallén, Anders.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lu, J.
    Jensen, J.
    Yu, L. D.
    Bertilsson, K.
    Wolborski, M.
    Singkarat, S.
    Possnert, G.
    Crystalline quality of 3C-SiC formed by high-fluence C+-implanted Si2007In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 253, no 11, p. 4836-4842Article in journal (Refereed)
    Abstract [en]

    Carbon ions at 40 keV were implanted into (1 0 0) high-purity p-type silicon wafers at 400 degrees C to a fluence of 6.5 x 10(17) ions/cm(2). Subsequent thermal annealing of the implanted samples was performed in a diffusion furnace at atmospheric pressure with inert nitrogen ambient at 1100 degrees C. Time-of-flight energy elastic recoil detection analysis (ToF-E ERDA) was used to investigate depth distributions of the implanted ions. Infrared transmittance (IR) and Raman scattering measurements were used to characterize the formation of SiC in the implanted Si substrate. X-ray diffraction analysis (XRD) was used to characterize the crystalline quality in the surface layer of the sample. The formation of 3C-SiC and its crystalline structure obtained from the above mentioned techniques was finally confirmed by transmission electron microscopy (TEM). The results show that 3C-SiC is directly formed during implantation, and that the subsequent high-temperature annealing enhances the quality of the polycrystalline SiC.

  • 246. Intarasiri, S.
    et al.
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Razpet, A.
    Singkarat, S.
    Possnert, Göran
    Ion beam synthesis of silicon carbide2005In: PARTICLE BEAMS & PLASMA INTERACTION ON MATERIALS AND ION & PLASMA SURFACE FINISHING 2004 / [ed] Vilaithong, T; Boonyawan, D; Thongbai, C, 2005, Vol. 107, p. 51-54Conference paper (Refereed)
    Abstract [en]

    Formation and crystallization of a thin near-surface layer of silicon carbide on a silicon substrate, created by ion-beam synthesis (IBS), are discussed. 80 and 40 keV carbon ions were implanted into a (100) high-purity p-type silicon substrate at roorn temperature and 400 degrees C, respectively, using doses in excess of 10(17) ions/cm(2). Elastic recoil detection analysis (ERDA) technique, developed for routine atomic depth profiling at the Angstrom laboratory, Uppsala University, Sweden, was used to investigate the depth distributions of implanted-ions. Infrared transmittance measurement was used as an indication of SiC in the implanted Si substrate. For the samples implanted at high temperature, the results show the existence of a peak at 797 cm(-1), indicating the presence of beta-SiC, already directly formed during the implantation without post-implantation annealing. While for the samples implanted at room temperature, starting with the band of amorphous Si-C network, the crystalline SiC appears at the annealing temperature as low as 900 degrees C. In both cases, during further annealing in vacuum, the peak grows in height and narrows in width (according to the measured FWHM) with increasing annealing temperature, indicating a further growth of the SiC layer. However, for thermal annealing at 1000 T in a vacuum furnace the SiC crystallization was not completed and crystal imperfection where still present. Complementary to IR, Raman scattering measurements were performed. Although no direct evidence of SiC vibrations were observed, the appearance and disappearance of both Si-Si and C-C related bands points out to the formation of silicon and carbon clusters in the implanted layer.

  • 247. Intarasiri, S.
    et al.
    Kamwanna, T.
    Hallén, Anders.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Yu, L. D.
    Janson, M. S.
    Thongleum, C.
    Possnert, G.
    Singkarat, S.
    RBS and ERDA determinations of depth distributions of high-dose carbon ions implanted in silicon for silicon-carbide synthesis study2006In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 249, p. 859-864Article in journal (Refereed)
    Abstract [en]

    For ion beam synthesis of silicon carbide (SiC), a knowledge of the depth distribution of implanted carbon ions in silicon is crucial for successful development. Based on its simplicity and availability, we selected Rutherford backscattering spectrometry (RBS) as an analysis technique for this purpose. A self-developed computer program dedicated to extract depth profiles of lighter impurities in heavier matrix is established. For control, calculated results are compared with an other ion beam analysis (IBA) technique superior for studying lighter impurity in heavier substrate i.e. elastic recoil detection analysis (ERDA). The RBS was performed with a 1.7-MV Tandetron accelerator using He2+ as the probe ions. The ERDA was performed with a 5-MV Pelletron accelerator using I8+ as the probe ions. This work shows that the RBS-extracted data had no significant deviations from those of ERDA and simulations by SRIM2003 and SIMPL computer codes. We also found that annealing at temperatures as high as 1000 degrees C had quite limited effect on the redistribution of carbon in silicon.

  • 248. Intarasiri, S.
    et al.
    Yu, L. D.
    Singkarat, S.
    Hallén, Anders.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lu, J.
    Ottosson, M.
    Jensen, J.
    Possnert, G.
    Effects of low-fluence swift iodine ion bombardment on the crystallization of ion-beam-synthesized silicon carbide2007In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 101, no 8Article in journal (Refereed)
    Abstract [en]

    Ion beam synthesis using high-fluence carbon ion implantation in silicon in combination with subsequent or in situ thermal annealing has been shown to be able to form nanocrystalline cubic SiC (3C-SiC) layers in silicon. In this study, a silicon carbide layer was synthesized by 40-keV C-12(+) implantation of a p-type (100) Si wafer at a fluence of 6.5x10(17) ions/cm(2) at an elevated temperature. The existence of the implanted carbon in Si substrate was investigated by time-of-flight energy elastic recoil detection analysis. The SiC layer was subsequently irradiated by 10-30 MeV I-127 ions to a very low fluence of 10(12) ions/cm(2) at temperatures from 80 to 800 degrees C to study the effect on the crystallization of the SiC layer. Infrared spectroscopy and Raman scattering measurement were used to monitor the formation of SiC and detailed information about the SiC film properties was obtained by analyzing the peak shape of the Si-C stretching mode absorption. The change in crystallinity of the synthesized layer was probed by glancing incidence x-ray diffraction measurement and transmission electron microscopy was also used to confirm the results and to model the crystallization process. The results from all these measurements showed in a coherent way that the synthesized structure was a polycrystalline layer with nanometer sized SiC crystals buried in a-Si matrix. The crystallinity of the SiC layer was enhanced by the low-fluence swift heavy ion bombardment and also favored by higher energy, higher fluence, and higher substrate temperature. It is suggested that electronic stopping plays a dominant role in the enhancement.

  • 249. Isaksson, M.
    et al.
    Chacinski, Marek
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wesstrom, J. -O
    10 Gb/s direct modulation of 40 nm tunable modulated-grating Y-branch laser2005In: Optical Fiber Communication Conference, 2005. Technical Digest. OFC/NFOEC, 2005, Vol. 2, p. 117-119Conference paper (Refereed)
    Abstract [en]

    High speed properties of a directly modulated widely tunable MG-Y laser have been evaluated. Small signal response and 10 Gb/s NRZ modulation were performed within the 40 nm tuning range.

  • 250.
    Isaksson, Mats
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Chacinski, Marek
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wesström, J. -O
    10 Gb/s direct modulation of 40 nm tunable modulated-grating Y-branch laser2006In: OFC/NFOEC Technical Digest, Optical Society of America, 2006Conference paper (Refereed)
    Abstract [en]

    High speed properties of a directly modulated widely tunable MG-Y laser have been evaluated. Small signal response and 10 Gb/s NRZ modulation were performed within the 40 nm tuning range.

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