STRAIN-INDUCED INTERDIFFUSION AT SEMICONDUCTOR INTERFACES

The relative stability of ideal-geometry versus intermixed buried semiconductor interfaces is studied by first-principles density-functional methods. It is found that although intermixing of the ideal lattice-matched GaAs/AlAs (001) interface costs energy, intermixing is an energy-lowering process at coherent strained-layer (001) interfaces of lattice-mismatched materials. Intermixing an ideal strained-layer (001) interface lowers the energy mainly because it partially relieves the strain in a local region near the interface. It is thus expected that lattice-mismatched interfaces will have a greater degree of atomic-scale microroughness than similar interfaces of lattice-matched materials.