Phase equilibria in the semiconductor-rich portions of the Pt-Ti-Ga-As andPt-Ti-In-As systems

Phase equilibria at 700 degrees C in the GaAs-rich portion of the Pt-Ti-Ga- As system and the InAs-rich portion of the Pt-Ti-In-As system have been inv estigated. These studies were undertaken to provide a better understanding of the metallurgy of contacts that contain both Pt and Ti on the semiconduc tors GaAs and InAs. The phases present in equilibrated samples were charact erized through X-ray diffraction and in some cases electron probe microanal ysis. This study reveals a tendency for Ti to form TiAs and Pt to form gall ides (indides) in thermodynamic equilibrium with GaAs (Ins) over a wide ran ge of Pt:Ti ratios. Thermodynamic stability of the semiconductor PtAs2, whi ch could play a role in the electrical characteristics of Ti/Pt/III-As cont acts, occurs when the Pt:Ti ratio exceeds 1:1 (1:2) on GaAs (InAs). (C) 199 8 Kluwer Academic Publishers.