| Research Abstract |
We clarified the formation dynamics, defect structures, and electronic structures of stacking-fault tetrahedron (SFT) and plane (SFP) during the semiconductor epitaxial growth, by using the first-principles calculations and the molecular dynamics
1.SFT during homo-epitaxy;
We investigated the SFT generation on Cl-adsorbed Si(111) surfaces and clarified that (1) the dome-like structure is generated on Cl atoms and becomes the core apex of the SFT, (2) the SFT ridges stabilize by producing Si-Si dimer structures, (3) all the apexes, ridges and surfaces of the SFT work as quantum-well potentials for electrons and holes, and (4) the SFT thermally annihilates due to the diffusion of dislocations.
2.SFT during hetero-epitaxy;
We studied the ZnSe growth on the GaAs surfaces and clarified that (1) the complex made of anti-site anions and vacancies originating from the interface heterovalent bonds promotes the formation of the SFT core-apex structure, and (2) the SFT density increases when the As coverage or the Se supply increases. These results explain a lots of experiments.
3.SFP at interfaces;
We studied the metal/semiconductor interfaces and clarified that (1) when the electronegativity of metal is large as in the case of Au/Si interface, the inter-diffusion of Au and Si, easily occurs at the interface, (2) when the electronegativity of metal is small as in the case of Al/AlN, the metal layers have the similar structure to the substrate and induce the surface-polarity conversion, and (3) at the lattice-mismatched interfaces such as InAs/GaAs, the intermixing of cation atoms occurs and the cation dimers appear on the surface, which become the core structures of dislocations.
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