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Title: Damage accumulation in nitrogen implanted 6H-SiC: Dependence on the direction of ion incidence and on the ion fluence

Abstract

The influence of crystallographic orientation and ion fluence on the shape of damage distributions induced by 500 keV N{sup +} implantation at room temperature into 6H-SiC is investigated. The irradiation was performed at different tilt angles between 0 degree sign and 4 degree sign with respect to the <0001> crystallographic axis in order to consider the whole range of beam alignment from channeling to random conditions. The applied implantation fluence range was 2.5x10{sup 14}-3x10{sup 15} cm{sup -2}. A special analytical method, 3.55 MeV {sup 4}He{sup +} ion backscattering analysis in combination with channeling technique (BS/C), was employed to measure the disorder accumulation simultaneously in the Si and C sublattices of SiC with good depth resolution. For correct energy to depth conversion in the BS/C spectra, the average electronic energy loss per analyzing He ion for the <0001> axial channeling direction was determined. It was found that the tilt angle of nitrogen implantation has strong influence on the shape of the induced disorder profiles. Significantly lower disorder was found for channeling than for random irradiation. Computer simulation of the measured BS/C spectra showed the presence of a simple defect structure in weakly damaged samples and suggested the formation of a complexmore » disorder state for higher disorder levels. Full-cascade atomistic computer simulation of the ion implantation process was performed to explain the differences in disorder accumulation on the Si and C sublattices. The damage buildup mechanism was interpreted with the direct-impact, defect-stimulated amorphization model in order to understand damage formation and to describe the composition of structural disorder versus the ion fluence and the implantation tilt angle.« less

Authors:
; ; ; ; ; ; ;  [1];  [2];  [3]
  1. Research Institute for Technical Physics and Materials Science, P.O. Box 49, H-1525 Budapest (Hungary)
  2. (Hungary)
  3. (Germany)
Publication Date:
OSTI Identifier:
20982632
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 101; Journal Issue: 2; Other Information: DOI: 10.1063/1.2409609; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AMORPHOUS STATE; BACKSCATTERING; COMPUTERIZED SIMULATION; CRYSTALLOGRAPHY; ENERGY LOSSES; ENERGY-LOSS SPECTROSCOPY; HELIUM IONS; ION IMPLANTATION; IRRADIATION; KEV RANGE 100-1000; MEV RANGE 01-10; NITROGEN IONS; POINT DEFECTS; RANDOMNESS; SEMICONDUCTOR MATERIALS; SILICON CARBIDES; TEMPERATURE RANGE 0273-0400 K

Citation Formats

Zolnai, Z., Ster, A., Khanh, N. Q., Battistig, G., Lohner, T., Gyulai, J., Kotai, E., Posselt, M., Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest, and Institute of Ion Beam Physics and Materials Research, Forschungszentrum Rossendorf, P.O. Box 510119, D-01314 Dresden. Damage accumulation in nitrogen implanted 6H-SiC: Dependence on the direction of ion incidence and on the ion fluence. United States: N. p., 2007. Web. doi:10.1063/1.2409609.
Zolnai, Z., Ster, A., Khanh, N. Q., Battistig, G., Lohner, T., Gyulai, J., Kotai, E., Posselt, M., Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest, & Institute of Ion Beam Physics and Materials Research, Forschungszentrum Rossendorf, P.O. Box 510119, D-01314 Dresden. Damage accumulation in nitrogen implanted 6H-SiC: Dependence on the direction of ion incidence and on the ion fluence. United States. doi:10.1063/1.2409609.
Zolnai, Z., Ster, A., Khanh, N. Q., Battistig, G., Lohner, T., Gyulai, J., Kotai, E., Posselt, M., Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest, and Institute of Ion Beam Physics and Materials Research, Forschungszentrum Rossendorf, P.O. Box 510119, D-01314 Dresden. Mon . "Damage accumulation in nitrogen implanted 6H-SiC: Dependence on the direction of ion incidence and on the ion fluence". United States. doi:10.1063/1.2409609.
@article{osti_20982632,
title = {Damage accumulation in nitrogen implanted 6H-SiC: Dependence on the direction of ion incidence and on the ion fluence},
author = {Zolnai, Z. and Ster, A. and Khanh, N. Q. and Battistig, G. and Lohner, T. and Gyulai, J. and Kotai, E. and Posselt, M. and Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest and Institute of Ion Beam Physics and Materials Research, Forschungszentrum Rossendorf, P.O. Box 510119, D-01314 Dresden},
abstractNote = {The influence of crystallographic orientation and ion fluence on the shape of damage distributions induced by 500 keV N{sup +} implantation at room temperature into 6H-SiC is investigated. The irradiation was performed at different tilt angles between 0 degree sign and 4 degree sign with respect to the <0001> crystallographic axis in order to consider the whole range of beam alignment from channeling to random conditions. The applied implantation fluence range was 2.5x10{sup 14}-3x10{sup 15} cm{sup -2}. A special analytical method, 3.55 MeV {sup 4}He{sup +} ion backscattering analysis in combination with channeling technique (BS/C), was employed to measure the disorder accumulation simultaneously in the Si and C sublattices of SiC with good depth resolution. For correct energy to depth conversion in the BS/C spectra, the average electronic energy loss per analyzing He ion for the <0001> axial channeling direction was determined. It was found that the tilt angle of nitrogen implantation has strong influence on the shape of the induced disorder profiles. Significantly lower disorder was found for channeling than for random irradiation. Computer simulation of the measured BS/C spectra showed the presence of a simple defect structure in weakly damaged samples and suggested the formation of a complex disorder state for higher disorder levels. Full-cascade atomistic computer simulation of the ion implantation process was performed to explain the differences in disorder accumulation on the Si and C sublattices. The damage buildup mechanism was interpreted with the direct-impact, defect-stimulated amorphization model in order to understand damage formation and to describe the composition of structural disorder versus the ion fluence and the implantation tilt angle.},
doi = {10.1063/1.2409609},
journal = {Journal of Applied Physics},
number = 2,
volume = 101,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}
  • Disorder accumulation and amorphization in 6H-SiC single crystals irradiated with 2.0 MeV Au₂⁺ ions at temperatures ranging from 150 to 550 K have been investigated systematically based on 0.94 MeV D⁺ channeling analyses along the <0001> axis. Physical models have been applied to fit the experimental data and to interpret the temperature dependence of the disordering processes. Results show that defect-stimulated amorphization in Au₂⁺-irradiated 6H-SiC dominates the disordering processes at temperatures below 500 K, while formation of clusters becomes predominant above 500 K. Two distinctive dynamic recovery stages are observed over the temperature range from 150 to 550 K, resultingmore » from the coupled processes of close-pair recombination and interstitial migration and annihilation on both sublattices. These two stages overlap very well with the previously observed thermal recovery stages. Based on the model fits, the critical temperature for amorphization in 6H-SiC under the Au₂⁺ ion irradiation conditions corresponds to 501 +- 10 K.« less
  • Disorder accumulation and amorphization in 6H-SiC single crystals irradiated with 2.0 MeV Au{sup 2+} ions at temperatures ranging from 150 to 550 K have been investigated systematically based on 0.94 MeV D{sup +} channeling analyses along the <0001> axis. Physical models have been applied to fit the experimental data and to interpret the temperature dependence of the disordering processes. Results show that defect-stimulated amorphization in Au{sup 2+}-irradiated 6H-SiC dominates the disordering processes at temperatures below 500 K, while formation of clusters becomes predominant above 500 K. Two distinctive dynamic recovery stages are observed over the temperature range from 150 tomore » 550 K, resulting from the coupled processes of close-pair recombination and interstitial migration and annihilation on both sublattices. These two stages overlap very well with the previously observed thermal recovery stages. Based on the model fits, the critical temperature for amorphization in 6H-SiC under the Au{sup 2+} ion irradiation conditions corresponds to 501{+-}10 K.« less
  • The effects of implantation temperature and ion flux on damage accumulation on both the Si and C sublattices in 4H-SiC are investigated under 1.1 MeV Al irradiation at temperatures from 150 to 450 K. The rate of damage accumulation decreases dramatically and the damage profile sharpens due to significant dynamic recovery at temperatures close to the critical temperature for amorphization. At 450 K, the relative disorder and the density of planar defects increase rapidly with the increasing ion flux, exhibiting saturation at high ion fluxes. Planar defects are generated through the agglomeration of excess Si and C interstitials during irradiationmore » and post-irradiation annealing at 450 K. Termination of (0001) planes is attributed to the accumulation of vacancies. A volume expansion of {approx}8% is observed for the peak damage region.« less
  • Damage accumulation and annealing in 6H-silicon carbide (alpha-SiC) single crystals have been studied in situ using 2.0 MeV HeRBS in a <0001>-axial channeling geometry (RBS/C). The damage was induced by 550 keV Si ion implantation (30 degrees off normal) at a temperature of -110 degrees C, and the damage recovery was investigated by subsequent isochromal annealing (20 min) over the temperature range from -110 degrees C to 900 degrees C. At ion fluences below 7.5 X 10 13 Si/cm (0.04 dpa in the damage peak), only point defects appear to be created. Furthermore, the defects on the Si sublattice canmore » be completely recovered by thermal annealing at room temperature (RT), and recovery of defects on the C sublattice is suggested. At higher fluences of 6.6 x 10 15 Si/cm (-90 degrees C), an amorphous layer is created from the surface to a depth of 0.6 mu-m. Because of recovery processes at the buried crystalline-amorphous interface, the apparent thickness of this amorphous layer decreases slightly (<10%) with increasing temperature over the range from -90 degrees C to 600 degrees C.« less
  • Rapid thermal processing utilizing microwave energy has been used to anneal N, P, and Al ion-implanted 6H-SiC. The microwaves raise the temperature of the sample at a rate of 200{degree}C/min vs 10{degree}C/min for conventional ceramic furnace annealing. Samples were annealed in the temperature range of 1400-1700{degree}C for 2-10 min. The implanted/annealed samples were characterized using van der Pauw Hall, Rutherford backscattering, and secondary ion mass spectrometry. For a given annealing temperature, the characteristics of the microwave-annealed material are similar to those of conventional furnace anneals despite the difference in cycle time. 19 refs., 7 figs., 3 tabs.