EFFECT OF COLUMN III VACANCY ON ARSENIC PRECIPITATION IN LOW-TEMPERATURE-GROWN III-V ARSENIDES

Separately grown p-type, intrinsic, and n-type GaAs at low temperature s as well as a combined p-i-n structure have been used to study the fo rmation of As precipitates upon annealing at 800 degrees C. For the se parate structures, least precipitates have been noticed in the n-type material. In contrast, the highest density of precipitates appears in the n region for the p-i-n structure. In addition, an obvious band dep leted of precipitates, exists in the intrinsic region near the n-i int erface. A general vacancy model, including Fermi level effect and crys tal bonding strength (thermodynamic factor), has been developed to exp lain the current results as well as to predict As precipitation in var ious low temperature grown III-V heterostructures. (C) 1998 American I nstitute of Physics.