The dielectric degradation phenomena in gate oxides of MoSi2/thin n+poly-Si (2, and the SEM or TEM observations of textures of MoSi2, poly-Si, and gate oxide. From analyses, it was concluded that the local reaction of molybdenum silicide with poly-Si under the presence of a barrier, like the thick native oxide on poly-Si formed before MoSi2deposition, results in the damage to a gate oxide through a thin poly-Si layer during annealing. Based upon analytical results, a new MoSi2/thin poly-Si gate process without dielectric degradation has been developed, in which the direct MoSi2deposition on undoped poly-Si to suppress the native oxide growth and phosphorus implantation into MoSi2were introduced. The process provided a good dielectric strength of a gate oxide even to the device with a poly-Si layer as thin as 50 nm, an easy dry etching without undercutting of poly-Si, and stable device characteristics and reliabilities compatible to a conventional poly-Si gate process.