Process of fabricating semiconductor device having doped polysilicon layer without segregation of dopant impurity

摘要

An intentionally undoped amorphous silicon layer, a phosphorous doped amorphous silicon layer and a tungsten silicide layer are successively laminated on a gate oxide layer, and are patterned into a gate electrode of a field effect transistor; while a phosphosilicate glass layer over the gate electrode is being reflowed, the amorphous silicon layers are crystallized to a polysilicon layer, and phosphorous is less segregated at the boundary between the gate oxide layer and the polysilicon layer during the heat treatment.