Electrical and electron microscope studies of the annealing of tellurium-doped gallium arsenide

Hall effect measurements and electron microscope examination of tellurium-doped gallium arsenide crystals annealed at various temperatures indicate that tellurium and copper (present as a contaminant) produce a high population of matrix point defects which are probably simple vacancies. Annealing at temperatures below 1000°C causes the growth of intrinsic prismatic vacancy loops on {111} and {100} planes in association with decorations of precipitated copper. Heating to temperatures above 1000°C caused the copper and tellurium (in extrinsic stacking faults) to move back into solution, eventually changing the semiconductor from n to p type, and leading to the disappearance of both prismatic loops and stacking faults.