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  • 51. Kakanakova-Georgieva, A.
    et al.
    Yakimova, R.
    Linnarsson, Margareta K.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Janzen, E.
    Site-occupying behavior of boron in compensated p-type 4H-SiC grown by sublimation epitaxy2002In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 91, no 5, p. 3471-3473Article in journal (Refereed)
    Abstract [en]

    Results from electrical and optical measurements of boron in compensated p-type 4H-SiC layers doped with Al, N, and B are reported. The layers were produced by sublimation epitaxy and characterized by secondary ion mass spectrometry, capacitance-voltage, and cathodoluminescence techniques. The boron-related contribution to the net acceptor concentration in the layers as well as the boron-related emission at similar to505 nm are detected for various growth conditions. The effect of the concentrations of the attendant impurities Al and N, concentration ratio of Al to N atoms, and growth rate on the site-occupying behavior of boron in the layers is discussed.

  • 52. Karim, A.
    et al.
    Hansson, G. V.
    Linnarsson, Margareta
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Influence of Er and O concentrations on the microstructure and luminescence of Si:Er/O LEDs2008In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 100, no Part 4, p. 042010-Article in journal (Refereed)
    Abstract [en]

    Erbium(Er)/Oxygen(O) doped Silicon (Si) layers grown by molecular beam epitaxy (MBE), can be used for fabricating Si-based light emitting diodes. The electroluminescence intensity from these layers depends sensitively on the formation of specific types of Er/O precipitates inside the Si host. We have performed a detailed microstructure analysis of MBE-grown Er/O doped Si layers using electron microscopy and combined it with secondary ion mass spectrometry (SIMS) measurements as well as electroluminescence studies. Two types of microstructures are observed in different samples with specific Er and O concentrations and grown using Er and Si co-evaporation in O ambient. The first type of microstructure consists of planar precipitates along (311) planes mostly initiated at the onset of the growth of the Si: Er/O layer. The second characteristic type of microstructure observed contain round precipitates of Er/O. Using analytical microscopy techniques it was revealed that the round precipitates contain a higher ratio of Er to O as compared to the planar precipitates of the first type. The planar precipitates normally result in structures with high electroluminescence intensity while the structures with round precipitates have low intensity.

  • 53. Karlsson, S
    et al.
    Adas, C
    Konstantinov, A
    Linnarsson, M K
    KTH, School of Information and Communication Technology (ICT).
    Growth of delta-doped SiC epitaxial layers2001In: SILICON CARBIDE AND RELATED MATERIALS, ECSCRM2000, 2001, Vol. 353-356, p. 563-566Conference paper (Refereed)
    Abstract [en]

    N- and p-type delta -doped SiC epitaxial layers have been grown by vapour phase epitaxy and characterised by SIMS and CV measurements. Different techniques of achieving delta -doped layers are examined. Doping profiles with FWHM from 1 to 10nm have been obtained at different peak concentrations.

  • 54. Karlsson, S.
    et al.
    Nordell, Nils
    Industrial Microelectronic Center (IMC), Sweden.
    Spadafora, F.
    Linnarsson, Margareta
    KTH.
    Epitaxial growth of SiC in a new multi-wafer VPE reactor1999In: Materials Science & Engineering: B. Solid-state Materials for Advanced Technology, ISSN 0921-5107, E-ISSN 1873-4944, Vol. 61-62, p. 143-146Article in journal (Refereed)
    Abstract [en]

    SiC epitaxial layers have been grown in a commercial multi-wafer reactor. Results from the initial growth runs are presented. The reactor is vertical and has a high speed rotating susceptor that can support up to six 50 mm diameter wafers. The surface morphology of the grown layers are specular and show no indication of step-bunching. The unintentional background doping is p-type in the low 10(15) cm(-3) range, consisting mainly of Al. Both N and Al have been used for doped layers showing wide doping range capability and sharp transients. The best uniformity in thickness and doping achieved so far on the same 35 mm wafer are +/- 7% and +/- 10%, respectively. (C) 1999 Elsevier Science S.A. All rights reserved.

  • 55. Kobayashi, Takane
    et al.
    Primetzhofer, Daniel
    Linnarsson, Margareta
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Ion-stimulated desorption in the medium-energy regime2014In: Japanese Journal of Applied Physics, ISSN 0021-4922, E-ISSN 1347-4065, Vol. 53, no 6, p. 060305-Article in journal (Refereed)
    Abstract [en]

    Ion-stimulated desorption in the medium-energy regime is investigated using a hydrogen rich Li2O sample. The desorbed yield dependencies for H+ and Li+ on incident ion species H-1(+) and He-4(+) in a medium energy regime are measured. For the mechanism of desorption it is considered that an inner shell electron vacancy is generated in oxygen atoms of the target by the ion impact. This inner shell vacant state is then filled by Auger transition of an electron from surrounding H or Li atoms. The resulting coulomb repulsion between H+ or Li+ and O+ leads to ejection of H+ or Li+ from the surface.

  • 56. Konstantinov, A.
    et al.
    Karlsson, S.
    Adås, C.
    Harris, C.
    Linnarsson, M.
    KTH, School of Information and Communication Technology (ICT).
    Investigation of lo-hi-lo and delta-doped silicon carbide structures2001In: Materials Research Society Symposium - Proceedings, Boston, MA, 2001, Vol. 640, p. H2.4.1-H2.4.6Conference paper (Refereed)
    Abstract [en]

    Feasibility of lo-hi-lo and delta-doped structures for evaluation of high-field silicon carbide material properties is investigated. Delta-doped structures are grown using the hot-wall CVD technique. Aluminum and nitrogen doping profiles are demonstrated with FWHM below 10 nm. Nitrogen doping transients are found to be slower than those for aluminum. The growth interrupt technique has been developed for achieving narrow nitrogen doping peaks. Lo-hi-lo structures were fabricated using the implantation-and-regrowth technique. Structures with confined avalanche multiplication are demonstrated using the lo-hi-lo and delta doping techniques. The effect of substrate imperfections on early avalanche breakdown is investigated using confined avalanche multiplication devices.

  • 57. Kuznetsov, A.Yu.
    et al.
    Christensen, J. S.
    Linnarsson, M. K.
    KTH, School of Information and Communication Technology (ICT).
    Svensson, B. G.
    Radamson, H. H.
    Grahn, J.
    Landgren, G.
    Diffusion of phosphorus in strained Si/SiGe/Si heterostructures1999In: Materials Research Society Symposium - Proceedings, Vol. 568, no Warrendale, PA, United States, p. 271-276Article in journal (Refereed)
    Abstract [en]

    Phosphorus diffusion in a biaxially compressed Si0.87Ge0.13 film has been investigated in the temperature range of 810-900 °C. A significant enhancement of the P diffusion in the biaxially compressed Si0.87Ge0.13 in comparison with P diffusion in Si is observed. Injection of Si self-interstitials (I) during oxidation of a Si-cap in Si/Si0.87Ge0.13/Si heterostructures is used to characterize the atomic mechanism of P diffusion in Si0.87Ge0.13. It is found that the upper limit of the interstitial fraction of the P diffusion in Si0.87Ge0.13 is 0.87 of that in Si. A comparison between B and P diffusivities in SiGe supports the hypothesis of the pairing-controlled mechanism for the diffusion of B in SiGe.

  • 58. Laube, M.
    et al.
    Schmid, F.
    Pensl, G.
    Wagner, G.
    Linnarsson, Margareta K.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Maier, M.
    Electrical activation of high concentrations of N+ and P+ ions implanted into 4H-SiC2002In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 92, no 1, p. 549-554Article in journal (Refereed)
    Abstract [en]

    Comparative Hall effect investigations are conducted on N- and P-implanted as well as on (N+P)-coimplanted 4H-SiC epilayers. Box profiles with three different mean concentrations ranging from 2.5x10(18) to 3x10(20) cm(-3) to a depth of 0.8 mum are implanted at 500 degreesC into the (0001)-face of the initially p-type (Al-doped) epilayers. Postimplantation anneals at 1700 degreesC for 30 min are conducted to electrically activate the implanted N+ and P+ ions. Our systematic Hall effect investigations demonstrate that there is a critical donor concentration of (2-5)x10(19) cm(-3). Below this value, N- and P-donors result in comparable sheet resistances. The critical concentration represents an upper limit for electrically active N donors, while P donors can be activated at concentrations above 10(20) cm(-3). This high concentration of electrically active P donors is responsible for the observed low sheet resistance of 35 Omega/square, which is about one order of magnitude lower than the minimum sheet resistance achieved by N implantation.

  • 59. LI, G
    et al.
    LINNARSSON, M
    KTH, School of Information and Communication Technology (ICT).
    JAGADISH, C
    ZN DELTA-DOPED GAAS GROWN BY METALORGANIC VAPOR-PHASE EPITAXY1995In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 154, p. 231-239Article in journal (Refereed)
    Abstract [en]

    A number of delta-doping parameters have been changed to study their effects on the hole concentration of Zn delta-doped GaAs grown by metalorganic vapour phase epitaxy using dimethylzinc (DMZn) as a doping precursor. We observed that the hole concentration is dependent on the DMZn partial pressure but independent of the gas now velocity in the reactor. A weak effect of the delta-doping time on the hole concentration infers that the near-equilibrium between the Zn adsorption and desorption can be reached very rapidly. In the regime of the delta-doping temperatures from 600 to 700 degrees C, the Zn desorption predominantly determines the hole concentration, and the Zn desorption activation energy obtained from the Arrhenius-type plot is 2.04 eV. Below 600 degrees C, however, the hole concentration departures from the Arrhenius-type relationship with the reciprocal delta-doping temperature, indicating that some other factors start to influence the Zn delta-doping concentration.

  • 60.
    Linnarsson, M
    et al.
    KTH, School of Information and Communication Technology (ICT).
    Janzen, E
    Monemar, B
    Kleverman, M
    Thilderkvist, A
    Electronic structure of the GaAs:Mn-Ga center1997In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 55, p. 6938-6944Article in journal (Refereed)
    Abstract [en]

    The excitation spectrum of the O.11-eV Mn acceptor in GaAs has been thoroughly investigated by uniaxial stress and Zeeman fourier transform infrared spectroscopy. The results give strong evidence for the 3d(5) + shallow hole model for the Mn-0 center. The deformation potentials as well as the g values determined for the hole are in close agreement with those previously reported for the 1S(3/2)(Gamma(8)) State for shallow accepters in GaAs. All experimental results are in accordance with a J = 1 ground-state level derived from exchange coupling of the shallow 1S(3/2)(Gamma(8)) hole and the S = 5/2 Mn- core. A splitting between J = 2 and J = 1 levels in the range from 9 to 12 meV is inferred and is considerably larger than the 2-3 meV splitting previously suggested.

  • 61.
    Linnarsson, M K
    et al.
    KTH, School of Information and Communication Technology (ICT).
    Forsberg, U
    Janson, M S
    Janzen, E
    Svensson, B G
    Incorporation of hydrogen (H-1 and H-2) into 4H-SiC during epitaxial growth2002In: SILICON CARBIDE AND RELATED MATERIALS 2001, PTS 1 AND 2, PROCEEDINGS, 2002, Vol. 389-3, p. 565-568Conference paper (Refereed)
    Abstract [en]

    The hydrogen depth distribution in 4H-SiC after epitaxial growth at 1600 degreesC has been studied in detail with secondary ion mass spectrometry. Both H-1 and H-2 have been employed as carrier gas to trace the origin of the incorporated hydrogen. In particular the substrate as a prospective hydrogen source has been considered. After growth H-2 is detected throughout the whole substrate (similar to400 mum) and a considerable quantity remains after annealing at 1500 degreesC for 15 minutes.

  • 62.
    Linnarsson, M K
    et al.
    KTH, School of Information and Communication Technology (ICT).
    Janson, M S
    Karlsson, S
    Schoner, A
    Nordell, N
    Svensson, B G
    Diffusion of light elements in 4H-and 6H-SiC1999In: Materials Science & Engineering: B. Solid-state Materials for Advanced Technology, ISSN 0921-5107, E-ISSN 1873-4944, Vol. 61-2, p. 275-280Article in journal (Refereed)
    Abstract [en]

    Deuterium and lithium were introduced in p-type SiC by implantation of 20 keV H-2(+) or 30 keV Li-7(+) ions in order to form a diffusion source. The samples were subsequently annealed in vacuum in the temperature range 400-700 degrees C for 0.25 to 16 h. Secondary ion mass spectrometry (SIMS) was used to measure the deuterium and the lithium distribution after heat treatments. Both deuterium and lithium readily decorate the bombardment-induced defects in the vicinity of the ion implantation profile and they are also trapped, most likely by residual boron impurities, during diffusion into the bulk. An effective diffusion coefficient, reflecting the dissociation of trapped lithium, with an activation energy of 2.1 eV is extracted for lithium diffusion in p-type 6H SIG. Furthermore, a capture radius for trapping (most likely by boron) of deuterium is estimated as 10 Angstrom. (C) 1999 Elsevier Science S.A. All rights reserved.

  • 63.
    Linnarsson, M K
    et al.
    KTH, School of Information and Communication Technology (ICT).
    Janson, M S
    Schoner, A
    Svensson, B G
    Aluminum and boron diffusion in 4H-SiC2003In: SILICON CARBIDE 2002-MATERIALS, PROCESSING AND DEVICES, 2003, Vol. 742, p. 291-301Conference paper (Refereed)
    Abstract [en]

    A brief survey is given of some recent result of boron diffusion in low doped n-type (intrinsic) and p-type 4H-SiC. Aluminum diffusion and solubility limit in 4H-SiC are also discussed. Ion implantation of boron has been performed in epitaxial material to form a diffusion source but also epitaxial 4H-SiC structures, with heavily boron or aluminum doped layers prepared by vapor phase epitaxy have been studied. Heat treatments have been made at temperatures ranging from 1100 to 2050degreesC for 5 minutes up to 64 h. Secondary ion mass spectrometry has been utilized for analysis. For boron diffusion in acceptor doped 4H-SiC, 4x10(19) Al atoms/cm(3), an activation energy of 5.3 eV has been determined and a strong dependence on Al content for the diffusion coefficient is revealed. Transient enhanced diffusion of ion-implanted boron in intrinsic 4H-SiC samples is discussed. Solubility limits of similar to1x10(20) Al/cm(3) (1700degreesC) and <1x10(20) B/cm(3) (1900degreesC) have been deduced.

  • 64.
    Linnarsson, M K
    et al.
    KTH, School of Information and Communication Technology (ICT).
    Janson, M
    Schoner, A
    Nordell, N
    Karlsson, S
    Svensson, B G
    Deuterium incorporation in acceptor doped epitaxial layers of 6H-SiC1998In: SILICON CARBIDE, III-NITRIDES AND RELATED MATERIALS, PTS 1 AND 2, 1998, Vol. 264-2, p. 761-764Conference paper (Refereed)
    Abstract [en]

    Deuterium is introduced in boron doped epitaxial layers of 6H-SiC by implantation of 30 keV H-2(+) ions in order to form a diffusion source. The samples were subsequently annealed in vacuum at 700 degrees C/16h, 800 degrees C/4h and 900 degrees C/4h. Using depth profiling by secondary ion mass spectrometry (SIMS), the distributions of deuterium at different levels of boron doping are studied. The deuterium concentration correlates with the boron concentration and at a level of similar to 10(18) cm(-3) a ratio H-2/B-11 larger than 0.5 is obtained. From capacitance-voltage (CV) measurements a decrease in the electrical carrier concentration by 50% is revealed after deuterium diffusion at 800 degrees C/4h. At 900 degrees C passivation of the boron accepters ceases but the H-2 atoms are still confined to the boron-doped regions and display no long range migration.

  • 65.
    Linnarsson, M K
    et al.
    KTH, School of Information and Communication Technology (ICT).
    Persson, P O A
    Bleichner, H
    Janson, M S
    Zimmermann, U
    Andersson, H
    Karlsson, S
    Yakimova, R
    Hultman, L
    Svensson, B G
    Precipitate formation in heavily Al-doped 4H-SiC layers2001In: SILICON CARBIDE AND RELATED MATERIALS, ECSCRM2000, 2001, Vol. 353-356, p. 583-586Conference paper (Refereed)
    Abstract [en]

    Epitaxially grown 4H-SiC structures with several heavily Al doped layers were used. The samples were annealed in Ar atmosphere in a RF-heated furnace between 1500 and 2900 degreesC for 0.5 to 3h. Secondary ion mass spectrometry (SIMS) was used to measure the aluminum concentration versus;depth as well as the lateral distribution (ion images). Transmission electron microscopy (TEM) was employed to study the crystallinity and determine phase composition after heat treatment. A solubility limit of 2x10(20) Al/cm(3) at 2000 degreesC is extracted. Ion images of the lateral Al distribution reveal a pronounced dependence on the Al content. Precipitate formation occurs after heat treatment at 1700 - 2000 degreesC when the Al concentration exceeds 2x10(20) cm(-3) and energy-filtered TEM (EFTEM) shows that the precipitates contain Al.

  • 66.
    Linnarsson, M K
    et al.
    KTH, School of Information and Communication Technology (ICT).
    Spetz, A L
    Janson, M S
    Ekedahl, L G
    Karlsson, S
    Schoner, A
    Lundstrom, I
    Svensson, B G
    Metal-contact enhanced incorporation of deuterium in 4H-and 6H-SiC2000In: SILICON CARBIDE AND RELATED MATERIALS - 1999 PTS, 1 & 2, 2000, Vol. 338-3, p. 937-940Conference paper (Refereed)
    Abstract [en]

    Deuterium was introduced in p-type SiC from a gas ambient. The samples were partially coated with 200 Angstrom thick metal layer of titanium, nickel, platinum or gold. Heat treatments were performed in the temperature range 500-800 degreesC during 4 h. Secondary ion mass spectrometry (SIMS) was used to measure the deuterium content after deuterium exposure. The catalytic metal coating is shown to play an important role for introducing deuterium into SiC. Nickel and platinum facilitate hydrogen incorporation in p-type SiC, which may be due to an increased hydrogen concentration at the metal/SiC interface and/or an increase the H+ ions to H ratio. No in-diffusion of deuterium is observed using titanium although large quantities of deuterium are stored in the titanium film. Furthermore, gold reveals an inert character and does not promote in-diffusion of deuterium.

  • 67.
    Linnarsson, Margareta
    et al.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Diffusion of alkali metals in SiC2014In: Silicon Carbide and Related Materials 2013, PTS 1 and 2, 2014, p. 297-300Conference paper (Refereed)
    Abstract [en]

    Diffusion of lithium, sodium and potassium in SiC has been studied by secondary ion mass spectrometry. The alkali metal diffusion sources have been introduced by ion implantation. Subsequent anneals have been carried out in vacuum or in Ar atmosphere in the temperature range 700 degrees C - 1500 degrees C for 5 min to 16 h. The bombardment-induced defects in the vicinity of the ion implanted profile are readily decorated by the implanted. In the bulk, the diffusing alkali metals are most likely trapped and detrapped at boron and/or other defects during diffusion. The diffusivity of the studied alkali metals decreases as the mass increases, Li+<Na+<K+, but the sodium mobility in SiC is substantial already at 1100 degrees C.

  • 68.
    Linnarsson, Margareta
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Janson, Martin S.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Forsberg, U.
    Janzen, E.
    In-diffusion, trapping and out-diffusion of deuterium in 4H-SiC substrates2006In: Silicon Carbide and Related Materials 2005, Pts 1 and 2 / [ed] Devaty, RP, 2006, Vol. 527-529, p. 637-640Conference paper (Refereed)
    Abstract [en]

    Incorporation of hydrogen/deuterium in n-, p-type, and semi-insulating 4H-SiC substrates during epitaxial growth at 1590 degrees C has been studied in detail by secondary ion mass spectrometry. Out-diffusion has been investigated in samples subsequently annealed at high temperatures. After the epitaxial growth, deuterium is detected throughout the entire substrates. Out-diffusion can be observed after anneals at 1300 degrees C, but traces of deuterium can still be found in samples annealed as high as 1700 degrees C. A trap limited diffusion mechanism is proposed with vacancy related hydrogen trapping centers in n-type and semi insulating 4H-SiC substrates.

  • 69.
    Linnarsson, Margareta K.
    KTH, Superseded Departments, Electronics.
    Compound semiconductors: defects and relocation of atoms during growth sputtering and diffusion1997Doctoral thesis, comprehensive summary (Other scientific)
  • 70.
    Linnarsson, Margareta K
    et al.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Audren, A.
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Manganese in 4H-SiC2010In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 645-648, p. 701-704Article in journal (Refereed)
    Abstract [en]

    Manganese diffusion in 4H-SiC for possible spintronic applications is investigated. Ion implantation is used to introduce manganese in n-type and p-type 4H-SiC and subsequent heat treatment is performed in the temperature range of 1400 to 1800 degrees C. The depth distribution of manganese is recorded by secondary ion mass spectrometry and Rutherford backscattering spectrometry in the channeling direction is employed for characterization of crystal disorder. After the heat treatment, the crystal order is improved and a substantial rearrangement of manganese is revealed in the implanted region. However, no pronounced manganese diffusion deeper into the sample is recorded.

  • 71.
    Linnarsson, Margareta K.
    et al.
    KTH.
    Ayedh, H. M.
    Hallén, Anders
    KTH, School of Electrical Engineering and Computer Science (EECS), Electronics, Integrated devices and circuits.
    Vines, L.
    Svensson, B. G.
    Surface erosion of ion-implanted 4H-SiC during annealing with carbon cap2018In: International Conference on Silicon Carbide and Related Materials, ICSCRM 2017, Trans Tech Publications Inc., 2018, Vol. 924, p. 373-376Conference paper (Refereed)
    Abstract [en]

    The stability/ erosion of the interface between a C-cap and 4H-SiC have been studied by secondary ion mass spectrometry (SIMS). Aluminum implantation has been used to monitor the position of the moving interface as well as to investigate the influence on the interface stability by the crystal quality of the 4H-SiC. After Al implantation a C-cap has been deposited by pyrolysis of photoresist. Subsequent annealing has been performed at 1900 and 2000 °C with durations between 15 minutes and 1 hour. SIMS measurements have been performed without removal of the C-cap. The surface remains smooth after the heat treatment, but a large amount of SiC material from the uppermost part of the wafer is lost. The amount of lost material is related to for instance annealing temperature, ambient conditions and ion induced crystal damage. This contribution gives a brief account of the processes governing the SiC surface decomposition during C-cap post implant annealing.

  • 72.
    Linnarsson, Margareta K.
    et al.
    KTH, Superseded Departments, Electronics.
    Doyle, J. P.
    Svensson, B. G.
    KTH, Superseded Departments, Electronics.
    Diffusion of hydrogen in 6H silicon carbide1996In: III-nitride, SiC and diamond materials for electronic devices: Proceedings of the Symposium, San Francisco, CA; UNITED STATES; 8-12 Apr. 1996., 1996, p. 625-630Conference paper (Other academic)
    Abstract [en]

    6H polytype silicon carbide (SiC) samples of n-type have been implanted with 50-keV H(+) ions and subsequently annealed at temperatures between 200 and 1150 C. Using depth profiling by secondary ion mass spectrometry, the motion of hydrogen is observed in the implanted region for temperatures above 700 C. A diffusion coefficient of about 10 exp -14 sq cm/s is extracted at 800 C with an approximate activation energy of about 3.5 eV. Hydrogen displays strong interaction with the implantation-induced defects, and stable hydrogen-defect complexes are formed. These complexes anneal out at temperatures in excess of 900 C, and are tentatively identified as carbon-hydrogen centers at a Si vacancy.

  • 73.
    Linnarsson, Margareta K.
    et al.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Manganese in silicon carbide2012In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 273, p. 127-130Article in journal (Refereed)
    Abstract [en]

    Structural disorder and relocation of implanted Mn in semi-insulating 4H-SiC has been studied. Subsequent heat treatment of Mn implanted samples has been performed in the temperature range 1400-2000 degrees C. The depth distribution of manganese is recorded by secondary ion mass spectrometry. Rutherford backscattering spectrometry has been employed for characterization of crystal disorder. Ocular inspection of color changes of heat-treated samples indicates that a large portion of the damage has been annealed. However, Rutherford backscattering shows that after heat treatment, most disorder from the implantation remains. Less disorder is observed in the [0 0 0 1] channel direction compared to [1 1 (2) over bar 3] channel direction. A substantial rearrangement of manganese is observed in the implanted region. No pronounced manganese diffusion deeper into the sample is recorded.

  • 74.
    Linnarsson, Margareta K.
    et al.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Sodium diffusion in 4H-SiC2014In: APL MATERIALS, ISSN 2166-532X, Vol. 2, no 9, p. 096106-Article in journal (Refereed)
    Abstract [en]

    Sodium diffusion has been studied in p-type 4H-SiC. Heat treatments have been performed from 1200 degrees C to 1800 degrees C for 1 min to 4 h. Secondary ion mass spectrometry has been used to measure the sodium distribution. We show that sodium has a considerable mobility at 1200 degrees C in p-type 4H-SiC. On the other hand for sodium atoms trapped at suitable sites the mobility is limited up to 1800 degrees C. Trap limited diffusion kinetics is suggested and an effective diffusivity has been extracted with an activation energy of 4 eV for sodium diffusion in p-type 4H-SiC.

  • 75.
    Linnarsson, Margareta K.
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Material Physics, MF.
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT), Electronics, Integrated devices and circuits.
    Khartsev, Sergiy
    KTH, School of Information and Communication Technology (ICT), Electronics, Integrated devices and circuits.
    Suvanam, Sethu Saveda
    KTH, School of Information and Communication Technology (ICT).
    Usman, Muhammad
    KTH, School of Information and Communication Technology (ICT), Electronics, Integrated devices and circuits.
    Interface between Al2O3 and 4H-SiC investigated by time-of-flight medium energy ion scattering2017In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 50, no 49, article id 495111Article in journal (Refereed)
    Abstract [en]

    The formation of interfacial oxides during heat treatment of dielectric films on 4H-SiC has been studied. The 4H-SiC surface has been carefully prepared to create a clean and abrupt interface to Al2O3. An amorphous, 3 nm thick, Al2O3 film has been prepared on 4H-SiC by atomic layer deposition and rapid thermal annealing was then performed in N2O ambient at 700 degrees C and 1100 degrees C during 1 min. The samples were studied by time-of-flight medium energy ion scattering (ToF-MEIS), with sub-nanometer depth resolution and it is seen that, at both annealing temperatures, a thin SiOx (1 <= x <= 2) is formed at the interface. Our results further indicate that carbon remains in the silicon oxide in samples annealed at 700 degrees C. Additional electrical capacitance voltage measurements indicate that a large concentration of interface traps is formed at this temperature. After 1100 degrees C annealing, both MEIS and XRD measurements show that these features disappear, in accordance with electrical data.

  • 76.
    Linnarsson, Margareta K.
    et al.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Åström, J.
    Primetzhofer, D.
    Legendre, S.
    Possnert, G.
    New beam line for time-of-flight medium energy ion scattering with large area position sensitive detector2012In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 83, no 9, p. 095107-Article in journal (Refereed)
    Abstract [en]

    A new beam line for medium energy ion mass scattering (MEIS) has been designed and set up at the Angstrom laboratory, Uppsala University, Sweden. This MEIS system is based on a time-of-flight (ToF) concept and the electronics for beam chopping relies on a 4 MHz function generator. Repetition rates can be varied between 1 MHz and 63 kHz and pulse widths below 1 ns are typically obtained by including beam bunching. A 6-axis goniometer is used at the target station. Scattering angle and energy of backscattered ions are extracted from a time-resolved and position-sensitive detector. Examples of the performance are given for three kinds of probing ions, H-1(+), He-4(+), and B-11(+). Depth resolution is in the nanometer range and 1 and 2 nm thick Pt layers can easily be resolved. Mass resolution between nearby isotopes can be obtained as illustrated by Ga isotopes in GaAs. Taking advantage of the large size detector, a direct imaging (blocking pattern) of crystal channels are shown for hexagonal, 4H-SiC. The ToF-MEIS system described in this paper is intended for use in semiconductor and thin film areas. For example, depth profiling in the sub nanometer range for device development of contacts and dielectric interfaces. In addition to applied projects, fundamental studies of stopping cross sections in this medium energy range will also be conducted.

  • 77.
    Linnarsson, Margareta K.
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Isberg, J.
    Schöner, Adolf
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    A Comparison of Transient Boron Diffusion in Silicon, Silicon Carbide and Diamond2009In: SILICON CARBIDE AND RELATED MATERIALS 2007 / [ed] Suzuki A; Okumura H; Kimoto T; Fuyuki T; Fukuda K; Nishizawa S, 2009, Vol. 600-603, p. 453-456Conference paper (Refereed)
    Abstract [en]

    The boron diffusion in three kinds of group IV semiconductors: silicon, silicon carbide and synthetic diamond has been studied by secondary ion mass spectrometry. Ion implantation of 300 keV, B-11-ions to a dose of 2 x 10(14) cm(-2) has been performed. The samples are subsequently annealed at temperatures ranging from 800 to 1650 degrees C for 5 minutes up to 8 hours. In silicon and silicon carbide, the boron diffusion is attributed to a transient process and the level of out-diffusion is correlated to intrinsic carrier concentration. No transient, out-diffused, boron tail is revealed in diamond at these temperatures.

  • 78.
    Linnarsson, Margareta K.
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Janson, M. S.
    Zimmermann, U.
    Svensson, B. G.
    Persson, P. O. A.
    Hultman, L.
    Wong-Leung, J.
    Karlsson, S.
    Schoner, A.
    Bleichner, H.
    Olsson, E.
    Solubility limit and precipitate formation in Al-doped 4H-SiC epitaxial material2001In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 79, no 13, p. 2016-2018Article in journal (Refereed)
    Abstract [en]

    Heavily Al-doped 4H-SiC structures have been prepared by vapor phase epitaxy. Subsequent anneals have been carried out in an Ar atmosphere in a rf-heated furnace between 1500 degreesC and 2000 degreesC for 0.5 to 3 h. Secondary ion mass spectrometry has been utilized to obtain Al concentration versus depth as well as lateral distributions (ion images). Transmission electron microscopy (TEM) has been employed to study the crystallinity and determine phase composition after heat treatment. A solubility limit of similar to 2x10(20) Al/cm(3) (1900 degreesC) is extracted. Three-dimensional ion images show that the Al distribution does not remain homogeneous in layers heat treated at 1700 degreesC or above when the Al concentration exceeds 2x10(20) cm(-3). Al-containing precipitates are identified by energy-filtered TEM.

  • 79.
    Linnarsson, Margareta K.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Janson, Martin S.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Nordell, Nils
    KTH, School of Information and Communication Technology (ICT), Centres, Electrum Laboratory, ELAB.
    Wong-Leung, J.
    Schoner, A.
    Formation of precipitates in heavily boron doped 4H-SiC2006In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 252, no 15, p. 5316-5320Article in journal (Refereed)
    Abstract [en]

    Secondary ion mass spectrometry (SIMS) and transmission electron microscopy (TEM) are utilized to study precipitation and the solubility of B in 4H-SiC epitaxial layers super saturated with B. Heat treatments are performed in Ar atmosphere in an rf-heated furnace at temperatures between 1700 and 2000 degrees C. SIMS ion images, and TEM micrographs reveal the formation of two types of precipitates where the larger, more thermally stable one is suggested to be B4C. The boron solubility is determined from SIMS depth profiles and is shown to follow the Arrhenius expression: 7.1 x 10(22) exp(-1.4 eV/k(B)T) cm(-3) over the studied temperature range.

  • 80.
    Linnarsson, Margareta K.
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Janson, Martin S.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Shöner, A.
    Konstantinov, A.
    Svensson, B.G.
    Boron diffusion in intrinsic, n-type and p-type 4H-SiC2004In: SILICON CARBIDE AND RELATED MATERIALS 2003, PRTS 1 AND 2 / [ed] Madar, R; Camassel, J, 2004, Vol. 457-460, p. 917-920Conference paper (Refereed)
    Abstract [en]

    The diffusion of boron in 4H-SiC has been studied by secondary ion mass spectrometry. Three kinds of epitaxial layers have been used, highly p-type, highly n-type and low doped n-type (intrinsic). A boron diffusion source has been introduced in the samples by ion implantation. Subsequent anneals have been carried out in Ar atmosphere in a RF-heated furnace between 1220degreesC and 2000degreesC for 5 min to 3 h. For the boron diffusion in the highly p-doped layer, 4x10(19) Al atoms/cm(3) an activation energy of 5.3 eV has been determined. A similar activation energy has been extracted in the highly n-doped layer, 1x10(19) N atoms/cm(3), although the absolute diffusivity values differ by four orders of magnitude. In the lightly n-doped layer, transient enhanced boron diffusion is observed at intrinsic conditions.

  • 81.
    Linnarsson, Margareta K.
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Janson, Martin S.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Zhang, J.
    Janzen, E.
    Svensson, B. G.
    Self-diffusion of C-12 and C-13 in intrinsic 4H-SiC2004In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 95, no 12, p. 8469-8471Article in journal (Refereed)
    Abstract [en]

    Self-diffusion of carbon (C-12 and C-13) in low-doped (intrinsic) 4H-SiC has been studied using secondary ion mass spectrometry. A two layer C-13 enriched structure with C-13/C-12 ratios of 0.01 and 0.1, respectively, have been prepared by vapor phase epitaxy. Subsequent anneals have been carried out in Ar atmosphere in a rf heated furnace between 2100 and 2350 degreesC for 15 min-40 h. The C-13 depth profiles reveal a strict roott evolution for the diffusion, and the extracted carbon self-diffusion coefficients closely follow an Arrhenius temperature dependence: D-*=8.4x10(2) exp(-8.50 eV/kT) cm(2)/s. The extracted D-* are found to be 5 orders of magnitude lower than previously reported for the same temperatures in C-14 radio-tracer experiments.

  • 82.
    Linnarsson, Margareta K.
    et al.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Kaiser, M.
    Liljedahl, R.
    Jokubavicius, V.
    Ou, Y.
    Wellmann, P.
    Ou, H.
    Syväjärvi, M.
    Lateral boron distribution in polycrystalline sic source materials2013In: Silicon Carbide And Related Materials 2012, Trans Tech Publications Inc., 2013, Vol. 740-742, p. 397-400Conference paper (Refereed)
    Abstract [en]

    Polycrystalline SiC containing boron and nitrogen are used in growth of fluorescent SiC for white LEDs. Two types of doped polycrystalline SiC have been studied in detail with secondary ion mass spectrometry: sintered SiC and poly-SiC prepared by sublimation in a physical vapor transport setup. The materials are co-doped materials with nitrogen and boron to a concentration of 1x1018 cm-3 and 1x1019 cm-3, respectively. Depth profiles as well as ion images have been recorded. According to ocular inspection, the analyzed poly-SiC consists mainly of 4H-SiC and 6H-SiC grains. In these grains, the boron concentration is higher and the nitrogen concentration is lower in the 6H-SiC compared to the 4H-SiC polytype. No inter-diffusion between grains is observed.

  • 83.
    Linnarsson, Margareta K.
    et al.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Khartsev, Sergiy
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Primetzhofer, D.
    Possnert, G.
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    ToF-MEIS stopping measurements in thin SiC films2014In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 332, p. 130-133Article in journal (Refereed)
    Abstract [en]

    Electronic stopping in thin, amorphous, SiC films has been studied by time-of-flight medium energy ion scattering and conventional Rutherford backscattering spectrometry. Amorphous SiC films (8, 21 and 36 nm) were prepared by laser ablation using a single crystalline silicon carbide target. Two kinds of substrate films, one with a lower atomic mass (carbon) and one with higher atomic mass (iridium) compared to silicon has been used. Monte Carlo simulations have been used to evaluate electronic stopping from the shift in energy for the signal scattered from Ir with and without SiC. The two kinds of samples are used to illustrate the strength and challenges for ToF-MEIS compared to conventional RBS.

  • 84.
    Linnarsson, Margareta K.
    et al.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Suvanam, Sethu Saveda
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Vines, L.
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Alkali metal re-distribution after oxidation of 4H-SiC2016In: 16th International Conference on Silicon Carbide and Related Materials, ICSCRM 2015, Trans Tech Publications Ltd , 2016, p. 677-680Conference paper (Refereed)
    Abstract [en]

    Relocation of alkali metals sodium, potassium and cesium during oxidation of 4H-SiC has been studied by secondary ion mass spectrometry. The alkali metal source has been introduced by ion implantation before oxidation into n- and p-type 4H-SiC samples. Dry oxidation of SiC has been performed at 1150 ºC during 4, 8 and 16 h. In the formed oxide, the main part of the alkali metals diffuses out via the SiO2 surface. Close to the moving SiO2/SiC interface, a minor amount of alkali metals is retained. In the SiC material, the main amount of implanted alkali atoms is not redistributed during the oxidation, although a minor amount diffuses deeper into the samples. For ptype 4H-SiC, the diffusion deeper into the samples of the studied alkali metals decreases as the mass increases, Na+&lt;K+&lt;Cs+, but the sodium mobility is substantial already at 1150 °C.

  • 85.
    Linnarsson, Margareta K.
    et al.
    KTH, Superseded Departments, Electronics.
    Svensson, B. G.
    KTH, Superseded Departments, Electronics.
    Cascade mixing in AlxGa1-xAs/GaAs during sputter profiling by noble-gas ions1999In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 60, no 20, p. 14302-14310Article in journal (Refereed)
    Abstract [en]

    The effect of cascade mixing on profile broadening during secondary-ion mass spectrometry (SIMS) analysis has been thoroughly investigated for AlxGa1-xAs/GaAs structures of five different compositions (x=0.1, 0.3, 0.5, 0.73, or 1) and layers with varying thicknesses (from one monolayer to 1000 Å). The SIMS analyses were performed using primary sputtering ions of 20Ne+, 40Ar+, 84Kr+, and 136Xe+ with an impact energy (E) ranging from 1.8 to 13.2 keV and an angle of incidence, with respect to the surface normal (θ), from 62° to 35°. Within the experimental accuracy, the decay length of the trailing edge was found to be proportional to E1/2cosθ where the proportionality constant displays a relatively weak dependence on primary ion mass. However, the leading edge is strongly affected by the extension of the collision cascade as demonstrated by a comparison of the results for the different ions at a given energy. As long as the cascade is fully developed before reaching an interface no dependence on the sample depth is obtained for the profile broadening. Furthermore, the decay length for the trailing edges is extracted in the dilute limit and no effect of the marker thickness or the x value is revealed. A numerical treatment of the profile broadening within a diffusional model, where the diffusion coefficient is assumed to be proportional to the energy deposited in elastic collisions, gives a surprisingly good agreement with the experimental data.

  • 86.
    Linnarsson, Margareta K.
    et al.
    KTH, Superseded Departments, Electronics.
    Svensson, B. G.
    KTH, Superseded Departments, Electronics.
    Andersson, T. G.
    Wang, S. M.
    Paska, Z. F.
    Sputter profiling of AlGaAs/GaAs superlattice structures using oxygen and argon ions1993In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 70-71, no 1, p. 40-43Article in journal (Refereed)
    Abstract [en]

    Broadening of Al sputter profiles in AlxGa1-xAs/GaAs structures has been investigated using secondary ion mass spectrometry. The depth profiling was carried out with 32O+2 ions and 40Ar+ ions using net primary energies of 1.8, 2.2, 3.2 and 5.7 keV. The decay lengths of the Al profiles show a pronounced increase with increasing sputtering ion energy caused by ballistic mixing. Moreover, in the O+2 case the λ-values degrade with eroded depth, indicating that beam-induced surface roughening takes place during profiling and in particular, this holds for high x-values. The results are discussed in terms of a semi-empirical model for ion-beam-induced broadening developed by Zalm and Vriezema.

  • 87.
    Linnarsson, Margareta K.
    et al.
    KTH, Superseded Departments, Electronics.
    Svensson, B. G.
    KTH, Superseded Departments, Electronics.
    Paska, Z. F.
    Borglind, J.
    Influence of layer thickness and primary ion on profile broadening during sputtering of Al0.5Ga0.5As/GaAs structures1994In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, Vol. 85, no 1-4, p. 395-398Article in journal (Refereed)
    Abstract [en]

    Broadening of secondary ion mass spectrometry depth profiles for Al in Al0.5Ga0.5As/GaAs structures, where the layer thicknesses vary from two monolayers to 1000 Å, is investigated. The experiments were performed in the net primary energy range 1.8–13.2 keV with 40Ar+ ions and 84Kr+ ions. The broadening is mainly determined by ballistic mixing, and no dependence on the Al0.5Ga0.5As layer thickness is revealed. Good agreement is found with a semi-empirical mixing model published recently by Zalm and Vriezema and [Nucl. Instr. and Meth. B 67 (1992) 467] although a small contribution from surface roughness occurs. The surface roughness develops initially but saturates already after the first Al0.5Ga0.5As layer.

  • 88.
    Linnarsson, Margareta K.
    et al.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Wong-Leung, J.
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Khartsev, Sergiy I.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Grishin, Alexander M.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Mn implantation for new applications of 4H-SiC2012In: Silicon Carbide and Related Materials 2011 / [ed] Devaty, RP; Dudley, M; Chow, TP; Neudeck, PG, Trans Tech Publications Inc., 2012, Vol. 717-720, p. 221-224Conference paper (Refereed)
    Abstract [en]

    Structural disorder and lattice recovery of high dose, manganese implanted, semiinsulating, 4H-SiC have been studied by secondary ion mass spectrometry, Rutherford backscattering in channeling directions, visible-to-near infrared optical spectroscopy as well as with transmission electron microscopy. After heat treatment at 1400 and 1600 °C, a substantial rearrangement of manganese is observed in the implanted region. However, the crystal has not been fully recovered. More disorder remains in the [1123] compared to the [0001] channel direction. Stacking faults, voids and 3C inclusions are observed in the implanted region. A Mn containing phase has most likely formed.

  • 89.
    Linnarsson, Margareta K.
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Zimmermann, U.
    Wong-Leung, J.
    Schoner, A.
    Janson, M. S.
    Jagadish, C.
    Svensson, B. G.
    Solubility limits of dopants in 4H-SiC2003In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 203, p. 427-432Article in journal (Refereed)
    Abstract [en]

    Epitaxial 4H-SiC structures with heavily boron or aluminium doped layers have been prepared by vapour phase epitaxy. The samples have been annealed in Ar atmosphere in an RF-heated furnace between 1700 and 2000 degreesC for 45 min to 64 h. Secondary ion mass spectrometry has been employed to obtain depth distributions as well as lateral distributions (ion imaging) for boron and aluminium. Transmission electron microscopy has been used to study the crystallinity and determine phase composition. Solubility limits of similar to 1 x 10(20) Al/cm(3) (1700 degreesC) and < 1 x 10(20) B/cm(3) (1900 degreesC) have been deduced.

  • 90. Manolis, G.
    et al.
    Gulbinas, K.
    Grivickas, V.
    Jokubaviius, V.
    Linnarsson, Margareta
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Syväjärvi, M.
    Temperature dependencies of free-carrier-absorption lifetime in fluorescent 6H-SiC layers2014In: IOP Conference Series: Materials Science and Engineering, 2014, no 1Conference paper (Refereed)
    Abstract [en]

    The nonradiative decay of majority electrons has been studied over a wide temperature range from 80 K to 600 K using the time-resolved free-carrier-absorption (FCA) technique. At high injection level of the highly-luminescent N-B codoped 6H-SiC epilayer, we revealed three main relaxation components of injected free electrons over ps-to-ms time ranges. By means of temperature dependency, two components can be ascribed to thermal activation of holes from a shallow (200 meV) and a deep (500 meV) acceptor. The third one, which has a hundred us-time scale, we attribute to minority hole recombination from the valance band into the electron trap (53 meV). This recombination channel seems to compete with the deep-acceptor (Boron) to-donor (Nitrogen) pair visible emission at and below 300 K.

  • 91. Monakhov, E.
    et al.
    Svensson, B. G.
    Linnarsson, Margareta K.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    La Magna, A.
    Privitera, V.
    Fortunato, G.
    Mariucci, L.
    Boron-enhanced diffusion in excimer laser annealed Si2004In: Materials Science & Engineering: B. Solid-state Materials for Advanced Technology, ISSN 0921-5107, E-ISSN 1873-4944, Vol. 114-15, p. 114-117Article in journal (Refereed)
    Abstract [en]

    The effect of excimer laser annealing (ELA) and rapid thermal annealing (RTA) on B redistribution in B-implanted Si has been studied by secondary ion mass spectrometry (SIMS) and spreading resistance probe (SRP). B has been implanted with an energy of 1 keV and a dose of 10(16) cm(-2) forming a distribution with a width of 20-30nm and a peak concentration of similar to5 x 10(21) cm(-3). It has been found that ELA with 10 pulses of the energy density of 850 mJ/cm(2) results in a uniform B distribution over the ELA-molten region with an abrupt profile edge. SRP measurements demonstrate good activation of the implanted B after ELA, with the concentration of the activated fraction (similar to10(21) cm(-3)) exceeding the solid solubility level. RTA (30 s at 1100degreesC) of the as-implanted and ELA-treated samples leads to a diffusion of B with diffusivities exceeding the equilibrium one and the enhancement is similar for both of the samples. It is also found that RTA decreases the activated B in the ELA-treated sample to the solid solubility limit (2 x 10(20) cm(-3)). The similarity of the B diffusivity for the as-implanted and ELA-treated samples suggests that the enhancement of the B diffusivity is due to the so-called boron-enhanced diffusion (BED). Possible mechanisms of BED are discussed.

  • 92. Monakhov, E. V.
    et al.
    Svensson, B. G.
    Linnarsson, Margareta K.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    La Magna, A.
    Italia, M.
    Privitera, V.
    Fortunato, G.
    Cuscuna, M.
    Mariucci, L.
    Boron distribution in silicon after excimer laser annealing with multiple pulses2005In: Materials Science & Engineering: B. Solid-state Materials for Advanced Technology, ISSN 0921-5107, E-ISSN 1873-4944, Vol. 124, p. 228-231Article in journal (Refereed)
    Abstract [en]

    We have studied B re-distribution in Si after excimer laser annealing (ELA) with multiple laser pulses. B was implanted using both B and BF2 ions with energies from 1 to 20 keV and doses of 1 x 10(14) and 1 x 10(15) cm(-2). ELA with the number of pulses from 1 to 100 was performed in vacuum with the sample kept at room temperature and 450 degrees C. Independently of the implantation parameters and the ELA conditions used, a peak in the B concentration is observed near the maximum melting depth after 10 pulses of ELA. A detailed study has revealed that B accumulates at the maximum melt depth gradually with the number of ELA pulses. An increase in the carrier concentration at the maximum melt depth is observed after ELA with 100 pulses. No structural defects have been detected by transmission electron microscopy in the region of the B accumulation.

  • 93. Monakhov, E. V.
    et al.
    Svensson, B. G.
    Linnarsson, Margareta K.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    La Magna, A.
    Italia, M.
    Privitera, V.
    Fortunato, G.
    Cuscuna, M.
    Mariucci, L.
    Boron distribution in silicon after multiple pulse excimer laser annealing2005In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 87, no 8Article in journal (Refereed)
    Abstract [en]

    We have studied B redistribution in Si after excimer laser annealing (ELA) with multiple laser pulses. B was implanted with energies of 1 and 10 keV and doses of 1x10(14) and 1x10(15) cm(-2). ELA with the number of pulses from 1 to 100 was performed at room temperature and 450 degrees C in vacuum. Irrespective of the implantation parameters and the ELA conditions used, a pile-up in the B concentration is observed near the maximum melting depth after ten pulses of ELA. Moreover, a detailed study has revealed that B accumulates at the maximum melt depth gradually with the number of ELA pulses. Besides, an increase in the carrier concentration is observed at the maximum melt depth, suggesting electrical activity of the accumulated B. Formation of Si-B complexes and vacancy accumulation during multiple ELA are discussed as possible mechanisms for the B build-up.

  • 94. Monakhov, E. V.
    et al.
    Svensson, B. G.
    Linnarsson, Margareta K.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    La Magna, A.
    Italia, M.
    Privitera, V.
    Fortunato, G.
    Cuscuna, M.
    Mariucci, L.
    Excimer laser annealing of B and BF2 implanted Si2005In: Materials Science & Engineering: B. Solid-state Materials for Advanced Technology, ISSN 0921-5107, E-ISSN 1873-4944, Vol. 124, p. 232-234Article in journal (Refereed)
    Abstract [en]

    We have performed a comparative study of B re-distribution and electrical activation after excimer laser annealing (ELA) of B and BF2 implanted Si. Chemical B concentration and electrical activation profiles were measured by secondary ion mass spectrometry (SIMS) and spreading resistance profiling (SRP), respectively. SIMS data demonstrate that the presence of F does not influence significantly the re-distribution of B during ELA. A dramatic contrast, however, can be observed in the electrical activation of the dopant in the B and BF2 implanted samples. While almost 100% electrical activation of B occurs in the B implanted samples, only 20-50% of the dopant can be activated by ELA in the BF2 implanted sample. Possible mechanisms causing the deactivation of B in the BF2 implanted samples after ELA are discussed.

  • 95. Monakhov, E. V.
    et al.
    Svensson, B. G.
    Linnarsson, Margareta K.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    La Magna, A.
    Italia, M.
    Privitera, V.
    Fortunato, G.
    Cuscuna, M.
    Mariucci, L.
    The effect of excimer laser pretreatment on diffusion and activation of boron implanted in silicon2005In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 87, no 19Article in journal (Refereed)
    Abstract [en]

    We have investigated the effect of excimer laser annealing (ELA) on transient enhanced diffusion (TED) and activation of boron implanted in Si during subsequent rapid thermal annealing (RTA). It is observed that ELA with partial melting of the implanted region causes reduction of TED in the region that remains solid during ELA, where the diffusion length of boron is reduced by a factor of similar to 4 as compared to the as-implanted sample. This is attributed to several mechanisms such as liquid-state annealing of a fraction of the implantation induced defects, introduction of excess vacancies during ELA, and solid-state annealing of the defects beyond the maximum melting depth by the heat wave propagating into the Si wafer. The ELA pretreatment provides a substantially improved electrical activation of boron during subsequent RTA.

  • 96. Monakhov, E. V.
    et al.
    Svensson, B. G.
    Linnarsson, Margareta K.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    La Magna, A.
    Privitera, V.
    Camalleri, M.
    Fortunato, G.
    Mariucci, L.
    Excimer laser annealing of shallow As and B doped layers2004In: Materials Science & Engineering: B. Solid-state Materials for Advanced Technology, ISSN 0921-5107, E-ISSN 1873-4944, Vol. 114-15, p. 352-357Article in journal (Refereed)
    Abstract [en]

    Excimer laser annealing (ELA) of As-, B- and BF2-implanted Si has been studied by secondary ion mass spectrometry (SIMS), spreading resistance probe (SRP) and transmission electron microscopy (TEM). The implantations have been performed in the energy range from I to 30 keV with doses of 10(15)-10(16) cm(-2). ELA has been carried out with the energy densities in the range of 600-1200 mJ/cm(2) and the number of laser pulses from 1 to 10. It is shown that ELA results in a more uniform dopant distribution over the doped region with a more abrupt profile edge as compared to those after rapid thermal annealing (RTA). Besides, in contrast to RTA, ELA demonstrates a highly confined annealing effect, where the distribution of dopants below the melting region is not affected. SRP measurements demonstrate almost complete activation of the implanted dopants after ELA, and TEM does not reveal extended defects in the ELA-treated samples. The depth of the doped layers, abruptness of the profiles and the total doping dose as a function of ELA energy density and number of laser pulses are investigated. Computer simulations of ELA show a good agreement with the experimental data.

  • 97. Monakhov, E. V.
    et al.
    Svensson, B. G.
    Linnarsson, Margareta K.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    La Magna, A.
    Spinella, C.
    Bongiorno, C.
    Privitera, V.
    Fortunato, G.
    Mariucci, L.
    Enhanced boron diffusion in excimer laser preannealed Si2005In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 86, no 15Article in journal (Refereed)
    Abstract [en]

    We have investigated boron diffusion during rapid thermal annealing in Si implanted with boron using an energy of 1 keV and a dose of 1 x 10(16) cm(-2). Two types of samples have been studied: As-implanted and pretreated with excimer laser annealing. For both types an enhanced diffusion of boron has been observed with an enhancement by a factor of 3-5 over the standard diffusion. It is suggested that the high concentration of implanted boron is a dominant factor for the diffusion enhancement as compared to the effect of implantation-induced damage. The data indicate that the proximity of the surface can also affect the boron diffusion enhancement.

  • 98. MONTELIUS, L
    et al.
    NILSSON, S
    SAMUELSON, L
    JANZEN, E
    AHLSTROM, M
    CHARACTERIZATION OF THE MN ACCEPTOR LEVEL IN GAAS1988In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 64, p. 1564-1567Article in journal (Refereed)
  • 99. Morvan, E
    et al.
    Godignon, P
    Vellvehi, M
    Hallen, A
    Linnarsson, M
    KTH, School of Information and Communication Technology (ICT).
    Kuznetsov, A Y
    Channeling implantations of Al+ into 6H silicon carbide1999In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 74, p. 3990-3992Article in journal (Refereed)
    Abstract [en]

    A strong channeling effect of Al+ ions implanted into crystalline SiC has been observed by Monte Carlo simulations and experiments especially designed to demonstrate this phenomenon have been performed. Depth distributions of implanted Al were measured for on- and controlled off-axis Al implantations using secondary ion mass spectrometry (SIMS). Much deeper and wider profiles are obtained for the on-axis implantations as compared to off-axis implants. For higher doses, the experiment also reveals the growth of an intermediate peak slightly deeper than the random peak. The origin of the intermediate peak can be understood by combining SIMS results with Monte Carlo simulations, which motivates the development of advanced simulation tools for the ion implantation process in SiC. (C) 1999 American Institute of Physics. [S0003-6951(99)01426-6].

  • 100. Morvan, E
    et al.
    Mestres, N
    Campos, F J
    Pascual, J
    Hallen, A
    Linnarsson, M
    KTH, School of Information and Communication Technology (ICT).
    Kuznetsov, A Y
    Damage reduction in channeled ion implanted 6H-SiC2000In: SILICON CARBIDE AND RELATED MATERIALS - 1999 PTS, 1 & 2, 2000, Vol. 338-3, p. 893-896Conference paper (Refereed)
    Abstract [en]

    We compare damage effects of “random” (off-axis) and [0001] aligned implants of 1.5 MeV Al into 6H-SiC. Both channeled and random equivalent SIMS profiles have been used to adjust model parameters of the simulator. Depth resolved Raman measurements show that at ion doses below similar to 5x10(14) cm(-2), the integral damage is reduced by a factor of similar to2.5 for the channeled implant. This confirms the corresponding reduction of defect concentrations predicted by simulations.

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