Investigation of Si/3C-SiC interface properties using classical molecular dynamics
A Samanta and I Grinberg, JOURNAL OF APPLIED PHYSICS, 124, 175110 (2018).
Molecular dynamics simulations were carried out for different structural models of the Si/3C-SiC interface using the Tersoff SiC potential that can model both Si and SiC. We find that the bonding at the Si/3C-SiC interface has a strong effect on the crystallization of the Si phase and that a degree of intermixing is present between the two materials with some C atoms migrating from the 3C-SiC (hereinafter referred to as SiC) into the Si region. The degree of intermixing is likely to exhibit a strong dependence on the temperature and most likely also increases with time, which would lead to changes in the Si/SiC interface during the life of the Si/SiC composite. The inter-mixing also creates disorder and defects of threefold and fivefold bonded atoms in the vicinity of the interfaces. In particular, 1111/2 < 110 > misfit dislocations were formed at all three types of interfaces (100), (110), and (111) in order to relieve the local stress due to lattice mismatch. Additionally, the Si(110)/SiC(110) and Si(111)/SiC(111) interfaces prepared at higher temperatures show the formation of the 1111/6 < 112 > partial dislocation which arises due to intrinsic stacking faults. We find that the bonding at the crystalline(c) c-Si/SiC interface is weaker than that in bulk crystalline Si, whereas bonding at the amorphous(a)-Si/SiC interface is stronger than that in amorphous Si. Therefore, the rupture in the yield stress occurs at the vicinity of the Si/SiC interface and in the Si region for the a-Si/SiC systems, respectively. Finally, for both bulk and Si/SiC interface systems, a strong variation of the yield strength with temperature was observed. Published by AIP Publishing.
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