LPCVD TUNGSTEN SILICIDE WITH TITANIUM UNDERLAYER.

Abstract

High-density VLSI circuits demands a metallization to match the intrinsic device switching speed. The CVD process which produces conformal and reproducible films is emerging as a key technology in the IC industry. Recently, refractory LPCVD tungsten silicide has been applied in the NMOS process as polycide due to its high conductivity, ability to withstand high temperatures, ease of high resolution and patterning, high-quality surface passivation, and other levels of metallization. However, the major problem encountered in the application of stoichiometric silicide is the poor adhesion and high resistivity at high temperature. To overcome these problems, a structure using transition-metal underlayers for LPCVD tungsten silicide has been developed. The characteristics are reported of such structure consisting of thin titanium layer between LPCVD tungsten silicide and polysilicon.