Heat-resistant ohmic and barrier contacts for GaAs-based microwave devices

Abstract

We studied barrier and ohmic contacts that are used when developing GaAs-based microwave devices. It is shown that Au-Mo-TiBx-n-GaAs barrier contacts have higher thermal stability than Au-Ti-n-GaAs ones. This is due to substantial slowdown of grain-boundary diffusion in Au-Mo-TiBx contacts resulting from use of amorphous TiBx layers as barrier material. A phase transition in them occurs at a temperature over 1000 °С. It was determined that use of TiBx as an antidiffusion layer in Au-TiBx-AuGe-n-GaAs ohmic contacts to Gunn diodes increases their service life as compared to the traditional Au-AuGe-n-GaAs ohmic contact.