The evolution of a-GaAs 1−xN x/c-GaAs interface states as a function of Ar-NH 3 plasma

Abstract

This work concerns investigations on electrical properties of amorphous GaAs 1−xN x thin films grown on GaAs substrates. Film deposition was carried out by RF sputtering of a GaAs target by adding a nitrogen carrier gas (NH 3) to an Ar plasma. Chemical etching of substrates followed by different plasma treatments (like reverse bias and/or NH 3 glow discharge) prior to film deposition have been studied. The effects of substrate and growth temperature and of total pressure in the reactor have been analysed. Electrical characteristics ( C– V and C– V( T)) have enabled us to put in evidence the evolution of interface states of the a-GaAs 1−xN x/c-GaAs junctions. The amorphous GaAs 1−xN x thin films are potentially interesting to be considered for GaAs-based MIS structures, due to their relatively high resistivity values, or as passivating layers on GaAs devices.