We proposed Si-rich tungsten silicide (WSix) films for the alternate gate electrode of deep-submicron metal-oxide-semiconductor (MOS) field effect transistors. The investigation of WSix films deposited directly on SiO2 indicated that the annealing of as-deposited films using a rapid thermal processor (RTP) results in low resistivity, as well as negligible fluorine (F) diffusion. Specifically, the resistivity of RTP-annealed samples at 800 degreesC for 3 min in vacuum was similar to 150 mu Ohm cm, and the irregular growth of an extra SiO2 layer due to F diffusion during annealing has not been observed. In addition, the analysis of the WSix-SiO2-Si (MOS) capacitors exhibits excellent electrical characteristics.