High-Temperature Oxidation and Vacuum Dissociation Studies on the A{111}and B{111}Surfaces of Gallium Arsenide

Abstract

Gatos and Lavine (8) have proposed a model to explain the difference in etching behavior of the A {111} and surfaces of gallium arsenide, indium antimonide, and related compounds. The model associates unshared electrons to the B surface atoms and not to the A surface atoms. High‐temperature oxidation of gallium arsenide has been undertaken to study directly the oxidation of both types of surfaces in order to test the proposed model. Experimental results verify the model. The B surface reacts with oxygen at a higher rate. Vacuum evaporation experiments on gallium arsenide A and B surfaces indicate that atoms from the B surface dissociate at a greater rate than from the A surface below 770°C. Above 800°C, the dissociation rates are equal, indicating a change of mechanism to “molecular” evaporation. The high‐temperature (>800°C) heat of dissociation of gallium arsenide has been determined as 112 kcal/mole.