Abstract
Ti/TiN/Ag ohmic contacts to p-type GaAs were studied. The contacts were formed by a solid phase reaction between titanium and GaAs. The interposed TiN film acts as an excellent diffusion barrier in two respects. It confines the reactions between titanium and GaAs, and it prevents the intermixing of the top silver layer with titanium and GaAs below. The contact resistivity of this metallization system is stable up to 500°C for 2 h.