Method of fabricating semiconductor device with polycide gate structure

Abstract

A method of fabricating a semiconductor device is provided, which makes it possible to form a TiSi polycide gate structure having a crack-free TiSi film and which eliminates the process to lower the resistivity of a TiSi film. The method comprises the steps of: (a) providing a semiconductor substrate having an active region formed by an isolation dielectric; (b) selectively forming a gate dielectric in the active region; (c) forming a polysilicon film on the gate dielectric; (d) forming a TiSi film on the polysilicon film while the substrate is kept at a temperature of approximately 750° C. or higher; and (e) patterning the polysilicon film and the TiSi film to form a gate electrode with a polycide structure. In the step (e), no phase transition of TiSi from amorphous or C-49 phase to the C-54 phase occurs. A barrier film may be additionally provided between the polysilicon and TiSi films. Preferably, the temperature of the substrate has a highest value of approximately 850° C. The step (d) may be carried out by sputtering, CVD, or evaporation.