Damage Accumulation and Defect Relaxation in 4H-SiC
A nonlinear dependence of damage disorder on dose is observed for both the Si and C sublattices in 4H-SiC under 2 MeV Au irradiation at 165 K. The relative disorder observed along the <4403> direction is much higher than that along the <0001> direction. Molecular dynamics (MD) simulations demonstrate that most single interstitial configurations are formed on the Si-C dimer rows that are parallel to the <0001> direction. As a result, these interstitials are shielded by the Si and C atoms on the lattice sites, which significantly reduces the contribution of these interstitials to the backscattering/reaction yield along the <0001> direction. During isochronal annealing below room temperature, the relative disorder decreases along the <0001> direction, as expected; however, the disorder is stable on the Si sublattice and increases slightly on the C sublattice along the <4403> direction due to relaxation of some metastable defects to lower energy configurations. As the annealing temperature increases, similar recovery behavior on both the Si and C sublattices along the <0001> direction indicates coupling of Si and C recovery processes; however, slightly higher recovery temperatures on the C sublattice along the <4403> direction suggests some decoupling of the Si and C recovery processes. Based on the structures and energetics of defects from MD simulations, new insights into defect configurations and relaxation processes are described.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 860022
- Report Number(s):
- PNNL-SA-40582; 3448; 8208; KC0201020; TRN: US0504861
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, 70(12):125203, 1-7, Vol. 70, Issue 12
- Country of Publication:
- United States
- Language:
- English
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