THERMAL-STABILITY OF PTSI CONTACT TO GEXSI1-X

Thermal stability of PtSi contact to epitaxial Ge0.5Si0.5/(100)Si has been investigated. The PtSi layer remained structurally and morphologically intact on the epitaxial Ge-Si alloy at temperatures around 650-degrees-C. When annealed at higher temperatures, PtSi penetrated locally into the alloy, although no chemical reaction was observed. The observed stability of PtSi is explained on the basis of a ternary Pt-Ge-Si equilibrium phase diagram. Other choices of contact compounds on Ge-Si alloys are also discussed.