Disclosed is a method for depositing a tungsten silicide layer on a wafer coated with a polysilicon layer in a CVD process chamber. A surface of the polysilicon layer is pre-treated by introducing a hydrogen compound gas including any elements among group III elements or group V elements of the periodic table into the CVD process chamber. The tungsten silicide layer is deposited on the polysilicon layer by introducing a silane source gas and a tungsten source gas into the CVD process chamber. Since the surface of the polysilicon layer is pre-treated using the hydrogen compound gas before the tungsten silicide layer is deposited on the polysilicon layer, void generation is prevented on an interfacial surface between the tungsten silicide layer and the polysilicon layer.