The thermal stability of thin layer transition and refractory metallizations on GaAs

Abstract

The thermal stability of vacuum deposited thin metallic layers (namely Ta, Cr, Cr–Au, Mo, Mo–Au and W) on GaAs for short (1 h) and long (∠150 h) thermal anneals at temperatures up to 550°C have been studied using Rutherford backscattering of helium ions, scanning electron microscopy with energy and wavelength dispersive x-ray analysis, and secondary ion mass spectrometry. We attempt to generalize the nature of thermal reactions of the metals with GaAs and the competing oxidation reactions in a humid/oxidizing atmosphere in terms of simple physiochemical considerations.