Physico-chemical studies of platinum-silicon interfaces

Abstract

Identifications of microscopic compositions in alloyed layers of heat-treated Pt-Si contacts and analysis of chemical kinetics of solid-solid reactions between Pt and Si have been carried out. The layer structure of the Pt-Si contact sequentially changes, through Pt-Pt_2Si-Si, Pt-Pt_2Si-PtSi-Si and Pt_2Si-PtSi-Si, into PtSi-Si during heat treatment at temperatures ranging from 200℃ to 700℃. The grown PtSi layer has the preferred crystallographic orientation in the [001] direction. The rate-determining process of the solid-solid reaction in the Pt-Si contact is the diffusion process of Si into Pt and/or platinum silicides. The rate constants are well represented by the following Arrhenius relationships: kp_t2Si=1.5×10^-3 exp (-24100/RT)cm^2/sec and kp_tSi=-2.5×10^-1 exp (-33900/RT)cm^2/sec.