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Title: Atomistic Simulations on the Thermal Stability of the Antisite Pair in 3C- and 4H-SiC

Abstract

The thermal stability of the first-neighbor antisite pair configurations in 3C- and 4H-SiC is investigated by a comprehensive atomistic study. At first the structure and energetics of these defects is determined in order to check the accuracy of the Gao-Weber interatomic potential used. The results are comparable with literature data obtained by the density-functional theory. Then, the lifetime of the antisite pair configurations is calculated for temperatures between 800 and 2500 K. Both in 3C- and 4H-SiC the thermal stability of the antisite pairs is rather low. In contrast to previous theoretical interpretations, the antisite pair can be therefore not correlated with the DI photoluminescence center that is stable to above 2000 K. The atomic mechanisms during the recombination of the antisite pair in 3C-SiC and of three antisite pair configurations in 4H-SiC is a modified concerted exchange. Due to the different sizes of the silicon and the carbon atoms, this process is not identical with the concerted exchange in Si. Two intermediate metastable configurations found during the recombination are similar to the bond defect in Si. Since the SiC lattice contains two types of atoms, there are also two different types of bond defects. The two bond defects canmore » be considered as the result of the incomplete recombination of a carbon vacancy and a neighboring mixed dumbbell interstitial. For selected temperatures the thermal stability of the antisite pair in 3C-SiC is investigated by molecular dynamics simulations that are based on the density-functional theory. Their results are very similar to those of the atomistic study, i.e. the Gao-Weber potential describes the antisite pair and its recombination reasonably well. The antisite pair in 4H-SiC with the two atoms on hexagonal sites has a slightly different formation energy than the other three antisite pair configurations in 4H-SiC. Its lifetime shows another dependence on the temperature, and its recombination is characterized by a separate motion of atoms.« less

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
881095
Report Number(s):
PNNL-SA-48239
8208; KC0201020; TRN: US200612%%701
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter; Journal Volume: 73; Journal Issue: 12
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; SILICON CARBIDES; CARBON; CRYSTAL DEFECTS; PHOTOLUMINESCENCE; RECOMBINATION; STABILITY; THERMODYNAMIC PROPERTIES; HYDRIDES; Antisite pair; computer simulatiuon; SiC; thermal stability; Environmental Molecular Sciences Laboratory

Citation Formats

Posselt, Matthias, Gao, Fei, and Weber, William J. Atomistic Simulations on the Thermal Stability of the Antisite Pair in 3C- and 4H-SiC. United States: N. p., 2006. Web. doi:10.1103/PhysRevB.73.125206.
Posselt, Matthias, Gao, Fei, & Weber, William J. Atomistic Simulations on the Thermal Stability of the Antisite Pair in 3C- and 4H-SiC. United States. doi:10.1103/PhysRevB.73.125206.
Posselt, Matthias, Gao, Fei, and Weber, William J. Fri . "Atomistic Simulations on the Thermal Stability of the Antisite Pair in 3C- and 4H-SiC". United States. doi:10.1103/PhysRevB.73.125206.
@article{osti_881095,
title = {Atomistic Simulations on the Thermal Stability of the Antisite Pair in 3C- and 4H-SiC},
author = {Posselt, Matthias and Gao, Fei and Weber, William J.},
abstractNote = {The thermal stability of the first-neighbor antisite pair configurations in 3C- and 4H-SiC is investigated by a comprehensive atomistic study. At first the structure and energetics of these defects is determined in order to check the accuracy of the Gao-Weber interatomic potential used. The results are comparable with literature data obtained by the density-functional theory. Then, the lifetime of the antisite pair configurations is calculated for temperatures between 800 and 2500 K. Both in 3C- and 4H-SiC the thermal stability of the antisite pairs is rather low. In contrast to previous theoretical interpretations, the antisite pair can be therefore not correlated with the DI photoluminescence center that is stable to above 2000 K. The atomic mechanisms during the recombination of the antisite pair in 3C-SiC and of three antisite pair configurations in 4H-SiC is a modified concerted exchange. Due to the different sizes of the silicon and the carbon atoms, this process is not identical with the concerted exchange in Si. Two intermediate metastable configurations found during the recombination are similar to the bond defect in Si. Since the SiC lattice contains two types of atoms, there are also two different types of bond defects. The two bond defects can be considered as the result of the incomplete recombination of a carbon vacancy and a neighboring mixed dumbbell interstitial. For selected temperatures the thermal stability of the antisite pair in 3C-SiC is investigated by molecular dynamics simulations that are based on the density-functional theory. Their results are very similar to those of the atomistic study, i.e. the Gao-Weber potential describes the antisite pair and its recombination reasonably well. The antisite pair in 4H-SiC with the two atoms on hexagonal sites has a slightly different formation energy than the other three antisite pair configurations in 4H-SiC. Its lifetime shows another dependence on the temperature, and its recombination is characterized by a separate motion of atoms.},
doi = {10.1103/PhysRevB.73.125206},
journal = {Physical Review. B, Condensed Matter},
number = 12,
volume = 73,
place = {United States},
year = {Fri Mar 31 00:00:00 EST 2006},
month = {Fri Mar 31 00:00:00 EST 2006}
}