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Linnarsson, Margareta K.ORCID iD iconorcid.org/0000-0002-0292-224X
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Publications (10 of 157) Show all publications
Linnarsson, M. K., Vines, L. & Hallén, A. (2021). Influence from the electronic shell structure on the range distribution during channeling of 40-300 keV ions in 4H-SiC. Journal of Applied Physics, 130(7), Article ID 075701.
Open this publication in new window or tab >>Influence from the electronic shell structure on the range distribution during channeling of 40-300 keV ions in 4H-SiC
2021 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 130, no 7, article id 075701Article in journal (Refereed) Published
Abstract [en]

Ion implantation is performed in H-4-SiC with B-11, Al-27, P-31, V-51, Ga-71, and As-75 ions using energies between 40 and 300 keV at various fluences along the [000-1] or the < 11-2-3 > axes. Secondary ion mass spectrometry is utilized to determine the depth distribution of the implanted elements. A Monte Carlo binary collision approximation (MC-BCA) code for crystalline targets is then applied to explain the influence of the electronic shell structure on electronic stopping and the obtained channeled ion depth distributions. The results show that, as the atomic number increases in a row of the periodic table, i.e., as the ionic radius decreases and the electron clouds densify, the interaction with the target electrons increases and the range is reduced. The decreased range is particularly pronounced going from Al-27 to P-31. The reduction in channeling depth is discussed in terms of electronic shells and can be related to the ionic radii, as defined by Kohn-Sham. It is shown that these shell effects in channeled implantations can easily be included in MC-BCA simulations simply by modifying the screening length used in the local treatment of electronic stopping in channels. However, it is also shown that, for vanadium ions with an unfilled d-shell, this simple model is insufficient to predict the electronic stopping in the channels.

Place, publisher, year, edition, pages
AIP Publishing, 2021
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-300231 (URN)10.1063/5.0054188 (DOI)000685162000003 ()2-s2.0-85113710930 (Scopus ID)
Note

QC 20210830

Available from: 2021-08-30 Created: 2021-08-30 Last updated: 2022-06-25Bibliographically approved
Sortica, M., Linnarsson, M., Wessman, D., Lohmann, S. & Primetzhofer, D. (2020). A versatile time-of-flight medium-energy ion scattering setup using multiple delay-line detectors. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 463, 16-20
Open this publication in new window or tab >>A versatile time-of-flight medium-energy ion scattering setup using multiple delay-line detectors
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2020 (English)In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 463, p. 16-20Article in journal (Refereed) Published
Abstract [en]

We present the most recent upgrades of the time-of-flight medium energy ion scattering (TOF-MEIS) system in Uppsala. The experimental chamber features a 6-axis goniometer with a sample annealing stage and two delay line detectors for composition analysis with high depth resolution and depth-resolved crystallography. The first detector has a large solid angle and can be moved circularly around the target position which allows to detect backscattered or transmitted ions. The second detector features increased flight distance from sample to detector resulting in enhanced energy resolution. A reduction from 1.4 keV to 0.4 keV is achieved for 100 keV He scattered from an Au surface for 1 ns time resolution, equivalent to a depth resolution of 6 Å. This detector is equipped with an electrostatic electrode in order to deflect charged particles, which allows to study the charge state for scattered ions in the medium energy regime.

National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-264364 (URN)10.1016/j.nimb.2019.11.019 (DOI)000518699900003 ()2-s2.0-85075313413 (Scopus ID)
Note

QC 20191126

Available from: 2019-11-26 Created: 2019-11-26 Last updated: 2024-01-18Bibliographically approved
Bathen, M. E., Linnarsson, M. K., Ghezellou, M., Hassan, J. U. & Vines, L. (2020). Influence of carbon cap on self-diffusion in silicon carbide. Crystals, 10(9), 1-11, Article ID 752.
Open this publication in new window or tab >>Influence of carbon cap on self-diffusion in silicon carbide
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2020 (English)In: Crystals, ISSN 2073-4352, Vol. 10, no 9, p. 1-11, article id 752Article in journal (Refereed) Published
Abstract [en]

Self-diffusion of carbon (12C and13C) and silicon (28Si and30Si) in 4H silicon carbide has been investigated by utilizing a structure containing an isotope purified 4H-28Si12C epitaxial layer grown on an n-type (0001) 4H-SiC substrate, and finally covered by a carbon capping layer (C-cap). The13C and30Si isotope profiles were monitored using secondary ion mass spectrometry (SIMS) following successive heat treatments performed at 2300–2450◦C in Ar atmosphere using an inductively heated furnace. The30Si profiles show little redistribution within the studied temperature range, with the extracted diffusion lengths for Si being within the error bar for surface roughening during annealing, as determined by profilometer measurements. On the other hand, a significant diffusion of13C was observed into the isotope purified layer from both the substrate and the C-cap. A diffusivity of D = 8.3 × 106 e−10.4/kBT cm2/s for13C was extracted, in contrast to previous findings that yielded lower both pre-factors and activation energies for C self-diffusion in SiC. The discrepancy between the present measurements and previous theoretical and experimental works is ascribed to the presence of the C-cap, which is responsible for continuous injection of C interstitials during annealing, and thereby suppressing the vacancy mediated diffusion.

Place, publisher, year, edition, pages
MDPI AG, 2020
Keywords
Carbon cap, Self-diffusion, Silicon carbide
National Category
Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-286436 (URN)10.3390/cryst10090752 (DOI)000581441700001 ()2-s2.0-85089843637 (Scopus ID)
Note

QC 20201218

Available from: 2020-12-18 Created: 2020-12-18 Last updated: 2022-06-25Bibliographically approved
Linnarsson, M. K., Hallén, A. & Vines, L. (2020). Intentional and unintentional channeling during implantation of p-dopants in 4h-sic. In: Materials Science Forum: . Paper presented at Materials Science Forum Vol. 1004, 29 September 2019 through 4 October 2019 (pp. 689-697). Trans Tech Publications Ltd, 1004
Open this publication in new window or tab >>Intentional and unintentional channeling during implantation of p-dopants in 4h-sic
2020 (English)In: Materials Science Forum, Trans Tech Publications Ltd , 2020, Vol. 1004, p. 689-697Conference paper, Published paper (Refereed)
Abstract [en]

Channeling phenomena during ion implantation have been studied for 50 keV11B, 100 keV27Al and 240 keV71Ga in 4H-SiC by secondary ion mass spectrometry and medium energy ion backscattering. The same projected range is expected for the used energies while the channeling tails are shown to be substantially different, for example, channeled71Ga ions may travel 5 times as deep as11B. Ion implantation has been performed both at room temperature (RT) and at 400 °C, where channeling effects are reduced for the 400 °C implantation compared to that of the RT due to thermal vibrations of lattice atoms. The temperature effect is pronounced for71Ga but nearly negligible for11B at the used energies. The channeling phenomena are explained by three-dimensional Monte Carlo simulations. For standard implantations, i.e. 4° off the c-direction, it is found that a direction in-between the [000-1] and the [removed] crystal channels, results in deep channeling tails where the implanted ions follow the [000-1] and the [removed] directions.

Place, publisher, year, edition, pages
Trans Tech Publications Ltd, 2020
Keywords
Binary collision approximation, Channeling implantation, Damage, Electronic stopping, Monte Carlo simulations, P-dopants, SIMS, Aluminum compounds, Gallium compounds, Ion implantation, Ions, Lattice vibrations, Monte Carlo methods, Secondary ion mass spectrometry, Silicon carbide, C implantations, Channeling effect, Channeling phenomena, Crystal channels, Ion backscattering, Projected range, Thermal vibration, Three-dimensional Monte-Carlo simulation, Vanadium compounds
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-285352 (URN)10.4028/www.scientific.net/MSF.1004.689 (DOI)2-s2.0-85089798399 (Scopus ID)
Conference
Materials Science Forum Vol. 1004, 29 September 2019 through 4 October 2019
Note

QC 20201130

Available from: 2020-11-30 Created: 2020-11-30 Last updated: 2024-01-10Bibliographically approved
Linnarsson, M. K., Hallén, A., Vines, L. & Svensson, B. (2019). Channeling implantations of p-type dopants into 4H-SiC at different tempertures. Materials Science Forum, 963, 382-385
Open this publication in new window or tab >>Channeling implantations of p-type dopants into 4H-SiC at different tempertures
2019 (English)In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 963, p. 382-385Article in journal (Refereed) Published
Abstract [en]

Channeling of B and Al ions in 4H-SiC(0001), has been investigated by secondary ion mass spectrometry (SIMS). Ion implantations have been performed between room temperature (RT) and 600 °C at various fluences. Before implantation, the major crystal axes were determined and the sample was aligned using the blocking pattern of backscattered protons. As expected, the depth distribution of the implanted ions along a crystal direction penetrates much deeper compared to nonchanneling directions. At elevated temperatures, the channeling depth for 100 keV Al-ions is decreased due to lattice vibrations. For 50 keV B-ions, the temperature effect is minor, indicating a smaller interaction between target atoms and B. Simulations has been performed using SIIMPL, a Monte Carlo simulation code based on the binary collision approximation, to predict experimental data and get a deeper insight in the channeling process.

Place, publisher, year, edition, pages
Trans Tech Publications Ltd, 2019
Keywords
Aluminum; Boron; ChannelingIon implantation; SIMS
National Category
Natural Sciences Physical Sciences Condensed Matter Physics
Research subject
Physics, Material and Nano Physics
Identifiers
urn:nbn:se:kth:diva-264231 (URN)10.4028/www.scientific.net/MSF.963.382 (DOI)2-s2.0-85071863753 (Scopus ID)
Funder
Swedish Research Council, E0510501
Note

QC 20191210

Available from: 2019-11-25 Created: 2019-11-25 Last updated: 2022-06-26Bibliographically approved
Linnarsson, M., Hallén, A. & Vines, L. (2019). Influence of a thin amorthous layer on de-channeling during aluminum implantation at different temperatures into 4H-SiC. Applied Physics A: Materials Science & Processing, 125(12), Article ID 849.
Open this publication in new window or tab >>Influence of a thin amorthous layer on de-channeling during aluminum implantation at different temperatures into 4H-SiC
2019 (English)In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 125, no 12, article id 849Article in journal (Refereed) Published
Abstract [en]

Ion implantation is an important technique in semiconductor processing and has become a key technology for 4H-SiC devices. Today, aluminum (Al) implantations are routinely used for p-type contacts, p(+)-emitters, terminations and many other applications. However, in all crystalline materials, quite a few ions find a path along a crystal channel, so-called channeling, and these ions travel deep into the crystal. This paper reports on the channeling phenomenon during Al implantation into 4H-SiC, and in particular, the influence of a thin native oxide will be discussed in detail. The effects of thermal lattice vibrations for implantations performed at elevated temperatures will also be elucidated. 100 keV Al ions have been implanted along the [000-1] direction employing samples with 4 degrees miscut. Before implantation, the samples have been aligned using the blocking pattern of backscattered protons. Secondary ion mass spectrometry has been used to record the Al depth distribution. To predict implantation profiles and improve understanding of the role of crystal structure, simulations were performed using the Monte-Carlo binary collision approximation code SIIMPL. Our results show that a thin surface layer of native oxide, less than 1 nm, has a decisive role for de-channeling of aligned implantations. Further, as expected, for implantations at elevated temperatures, a larger degree of de-channeling from major axes is present due to increased thermal vibrations and the penetration depth of channeled aluminum ions is reduced. The values for the mean-square atomic displacements at elevated temperatures have been extracted from experimental depth profiles in combination with simulations.

Place, publisher, year, edition, pages
Springer Berlin/Heidelberg, 2019
National Category
Physical Sciences Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-264238 (URN)10.1007/s00339-019-3144-1 (DOI)000498210100003 ()2-s2.0-85075212151 (Scopus ID)
Funder
Swedish Research Council, E0510501Swedish Research Council, 821-2012-5144Swedish Research Council, 2017-00646-9Swedish Foundation for Strategic Research , RIF14-0053The Research Council of Norway, 251131The Research Council of Norway, 245963
Note

QC 20191216

Available from: 2019-11-25 Created: 2019-11-25 Last updated: 2024-01-18Bibliographically approved
Linnarsson, M., Hallén, A. & Vines, L. (2019). Intentional and unintentional channeling during implantation of 51V ions into 4H-SiC. Semiconductor Science and Technology, 34, 1-10, Article ID 115006.
Open this publication in new window or tab >>Intentional and unintentional channeling during implantation of 51V ions into 4H-SiC
2019 (English)In: Semiconductor Science and Technology, ISSN 0268-1242, E-ISSN 1361-6641, Vol. 34, p. 1-10, article id 115006Article in journal (Refereed) Published
Abstract [en]

Ion implantation is a commonly used process step in 4H-SiC device manufacturing to implement precise concentrations of dopant atoms in selected areas and depths. This paper reports on vanadium (V) implantation into 4H-SiC(0001) and how the crystal lattice, with preferential directions, channels, for the ions, will influence the final dopant distribution. Concentration versus depth profiles of V-ions, intentionally and unintentionally channelled, has been recorded by secondary ion mass spectrometry. Ion implantations have been performed between 50 and 300 keV at various impact angles and fluence at room temperature as well as at elevated temperatures. Before ion implantation, the samples were aligned utilizing the blocking pattern of 100 keV backscattered protons. In addition to the aligned implantations, our standard beam line for ion implantation has been used for implantations in a 'random' direction using the wafer miscut angle of 4 degrees. The electronic stopping has been determined from these 'random' cases and the values have been used in 3D simulations to predict preferential crystallographic directions using SIIMPL, a Monte Carlo simulation code based on the binary collision approximation. The results show that, independent of the used impact angle there is always a probability that the vanadium ions will be steered into the [000-1] and the family of < 11-2-3 > crystal directions and therefore penetrate deep into the sample, resulting in unwanted 'spikes'. If the implantation is performed at elevated temperatures, a larger degree of dechanneling is present due to increased thermal vibrations and the penetration depth of vanadium is slightly reduced.

Keywords
aligned ion implantation; Monte-Carlo simulation; electronic stopping; binar collision approximation; SIMS
National Category
Physical Sciences Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-264235 (URN)10.1088/1361-6641/ab4163 (DOI)000507379500006 ()2-s2.0-85076049005 (Scopus ID)
Funder
Swedish Research Council, E0510501Swedish Research Council, 821-2012-5144Swedish Research Council, 2017-00646-9Swedish Foundation for Strategic Research , RIF14-0053The Research Council of Norway, NORFAB 197411/v30
Note

QC 20191204

Available from: 2019-11-25 Created: 2019-11-25 Last updated: 2024-01-18Bibliographically approved
Hallén, A., Linnarsson, M. & Vines, L. (2019). Recent advances in the doping of 4H-SiC by channeling ion implantation. In: Silicon Carbide and Related Materials 2018: . Paper presented at 12th European Conference on Silicon Carbide and Related Materials, ECSCRM 2018; Birmingham; United Kingdom; 2 September 2018 through 6 September 2018 (pp. 375-381). Trans Tech Publications Inc., 963
Open this publication in new window or tab >>Recent advances in the doping of 4H-SiC by channeling ion implantation
2019 (English)In: Silicon Carbide and Related Materials 2018, Trans Tech Publications Inc., 2019, Vol. 963, p. 375-381Conference paper, Published paper (Refereed)
Abstract [en]

The effect of lattice thermal vibrations on the channeling of 100 keV Al ions in 4H-SiC is investigated. By implanting at room temperature in the direction, the depth distribution of the incident ions is shown to be about 7 times deeper than for random implantations. At higher implantation temperatures, the channeling is reduced by the lattice vibrations and, for instance, at 600 °C implantation the distribution is about 3-4 times deeper than for a RT random implantation. The results are of technological interest for further development of implantation technology for 4H-SiC device manufacturing.

Place, publisher, year, edition, pages
Trans Tech Publications Inc., 2019
Series
Materials Science Forum, ISSN 0255-5476 ; 963
National Category
Physical Sciences Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-264360 (URN)10.4028/www.scientific.net/MSF.963.375 (DOI)2-s2.0-85071888219 (Scopus ID)9783035713329 (ISBN)
Conference
12th European Conference on Silicon Carbide and Related Materials, ECSCRM 2018; Birmingham; United Kingdom; 2 September 2018 through 6 September 2018
Note

QC 20191205

Available from: 2019-11-26 Created: 2019-11-26 Last updated: 2024-01-18Bibliographically approved
Suvanam, S. S., Usman, M., Martin, D., Yazdi, M. G., Linnarsson, M. K., Tempez, A., . . . Hallén, A. (2018). Improved interface and electrical properties of atomic layer deposited Al2O3/4H-SiC. Applied Surface Science, 433, 108-115
Open this publication in new window or tab >>Improved interface and electrical properties of atomic layer deposited Al2O3/4H-SiC
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2018 (English)In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 433, p. 108-115Article in journal (Refereed) Published
Abstract [en]

In this paper we demonstrate a process optimization of atomic layer deposited Al2O3 on 4H-SiC resulting in an improved interface and electrical properties. For this purpose the samples have been treated with two pre deposition surface cleaning processes, namely CP1 and CP2. The former is a typical surface cleaning procedure used in SiC processing while the latter have an additional weak RCA1 cleaning step. In addition to the cleaning and deposition, the effects of post dielectric annealing (PDA) at various temperatures in N2O ambient have been investigated. Analyses by scanning electron microscopy show the presence of structural defects on the Al2O3 surface after annealing at 500 and 800 °C. These defects disappear after annealing at 1100 °C, possibly due to densification of the Al2O3 film. Interface analyses have been performed using X-ray photoelectron spectroscopy (XPS) and time-of-flight medium energy ion scattering (ToF MEIS). Both these measurements show the formation of an interfacial SiOx (0 &lt; x &lt; 2) layer for both the CP1 and CP2, displaying an increased thickness for higher temperatures. Furthermore, the quality of the sub-oxide interfacial layer was found to depend on the pre deposition cleaning. In conclusion, an improved interface with better electrical properties is shown for the CP2 sample annealed at 1100 °C, resulting in lower oxide charges, strongly reduced flatband voltage and leakage current, as well as higher breakdown voltage.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
4H-SiC, Al2O3, High-K dielectric, Interface trap densities, Annealing, Atomic layer deposition, Cleaning, Deposition, Optimization, Scanning electron microscopy, Silicon carbide, Surface cleaning, Surface defects, Atomic layer deposited, Interface analysis, Interface trap density, Medium energy ion scattering, Structural defect, Surface cleaning procedure, X ray photoelectron spectroscopy
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-223127 (URN)10.1016/j.apsusc.2017.10.006 (DOI)000418883800014 ()2-s2.0-85031746823 (Scopus ID)
Funder
Swedish Research Council, D0674701
Note

QC 20180327

Available from: 2018-03-27 Created: 2018-03-27 Last updated: 2023-03-08Bibliographically approved
Usman, M., Suvanam, S. S., Linnarsson, M. & Hallén, A. (2018). Improving the quality of Al2O3/4H-SiC interface for device applications. Materials Science in Semiconductor Processing, 81, 118-121
Open this publication in new window or tab >>Improving the quality of Al2O3/4H-SiC interface for device applications
2018 (English)In: Materials Science in Semiconductor Processing, ISSN 1369-8001, E-ISSN 1873-4081, Vol. 81, p. 118-121Article in journal (Refereed) Published
Abstract [en]

The present paper focuses on the investigation of Al2O3/4H-SiC dielectric interface upon annealing, its consequent structural modifications, and the link to electrical properties. For this purpose, the test structures are prepared by depositing Al2O3, using atomic layer deposition (ALD), on low doped n-type 4H-SiC epitaxial layers. The structures are annealed from 300 degrees C to 1100 degrees C for different time duration (from 5 to 60 mins) and ambient such as, low vacuum (10(-1) Torr), N-2, and N2O. The structural studies on these samples are conducted using synchrotron-based high resolution x-ray photoelectron spectroscopy (HR-XPS), lab-based XPS, time of flight elastic recoil detection analysis (ToF-ERDA), and time of flight medium energy ion scattering (ToF-MEIS). The electrical response of capacitive structures is monitored through capacitance voltage (CV) measurements for as-deposited and annealed structures. It is found that the annealing at high temperatures, such as 1100 degrees C, and in N-2 or N2O environment, improves the dielectric properties due to the introduction of a thin layer of about 1 nm stable SiO2 between the Al2O3 and 4H-SiC.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
4H-SiC, Al2O3, Dielectric interface, XPS, Annealing, MEIS
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-226731 (URN)10.1016/j.mssp.2018.02.036 (DOI)000429746200020 ()2-s2.0-85044116454 (Scopus ID)
Funder
Swedish Research Council, D0674701
Note

QC 20180502

Available from: 2018-05-02 Created: 2018-05-02 Last updated: 2024-03-15Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-0292-224X

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