ELECTRICAL AND PHOTOELECTRICAL CHARACTERIZATION OF GAASXSY POLYCRYSTALLINE THIN-FILMS

Thin GaAsxSy films are deposited on Mo substrates by reactive radio-fr equency sputtering of a polycrystalline GaAs target by adding H2S to t he discharge gas (Ar). We used optical emission spectroscopy and mass spectrometry to study the As-S exchange reaction activity during sputt er deposition as a function of different sputtering parameters. The an alysis of electrical and photoelectrical properties of the Schottky ju nctions realised, Mo/GaAsS/Au, shows that with an increase in sulfur c oncentration there is: an improvement of the gold/semiconductor interf ace (decreasing interface index and increasing barrier height); a sign ificant lowering of grain boundary electrical activities. We have thus prepared a ternary polycrystalline compound GaAsxSy which presents pr omising electrical and photoelectrical properties, even for films as t hin as a few microns with grains of about one micron.