Origin of the High Resistance Region at the Epitaxial GaAs Layer‐Substrate Interface

Abstract

In order to find the reason for the high resistance region which appears at the interface between a vapor‐grown epitaxial layer and the substrate, epitaxial layers were grown by changing the substrate temperature or arsenic pressure in the reaction system. Heat‐treatment of substrates was also examined under a hydrogen atmosphere or in a flow of . A high resistance layer occurred even when the growth was initiated after the reaction had reached a steady state. While mere heat‐treatment in hydrogen changed the surface carrier density only slightly, the heat treatment in the flow of changed the region within a few microns from the surface of undoped substrates to almost semi‐insulating. The experimental results seem to indicate that the high resistance region is formed on surface or at the interface if the gas etching slightly overcomes the growth in a reaction system. Results of photoresponse and photoluminescence measurements on the high resistance region are also presented.