THE EFFECT OF EXCESS GALLIUM VACANCIES IN LOW-TEMPERATURE GAAS/ALAS/GAAS-SI HETEROSTRUCTURES

摘要

This article shows that the presence of low-temperature-grown GaAs (LT-GaAs) in LT-GaAs/A1As/ GaAs:Si heterostructures increases the Al/Ga interdiffusion at the heterostructure interfaces. The interdiffusion enhancement is attributed to the presence of Ca vacancies (V-Ga) in the As-rich LT-GaAs, which diffuses from a supersaturation of V-Ga frozen-in during sample growth. Chemical mapping, which distinguishes between the AlAs and GaAs lattices at an atomic scale, is used to measure the Al concentration gradient in adjacent GaAs:Si layers. A correlation is observed between the Al/Ga interdiffusion and the gate breakdown voltage in metal-insulator field-effect transistor structures containing LT-GaAs. (C) 1996 American Institute of Physics. References: 14