Interfacial reactions in Pt/InP contacts

Interfacial reactions in Pt/InP contacts were examined by transmission electron microscopy and Auger depth profiling. A solid state amorphization reaction occurred after the contacts were annealed for 60 s at 325°C. Crystallites were observed in the amorphous layer near the boundary between the amorphous phase and the remaining Pt upon annealing at 350°C. The predominant phase formed upon crystallization was polycrystalline Pt ₅InP. A cubic phase, which is most likely a supersaturated solution of phosphorus in Pt₃In, also formed. As the annealing temperature was increased, the reaction proceeded with the formation of phases that were richer in In and P. For 60 s anneals at temperatures of 500°C or greater, Pt-In phases and textured PtP₂ were observed, and the film/InP interface exhibited roughness on the scale of tens of nanometers. Both the Pt-In phases and PtP₂ were present at the film/InP interface.