Abstract: In fabricating a semiconductor device, when impurities are diffused from a silicon oxide layer containing the impurities to a semiconductor layer, a diffusion atmosphere is controlled so as to oxidize or reduce a specified impurity to thereby control the diffusion coefficient of the impurities in the silicon oxide layer. Thus, it is possible to form a diffusion layer having a desired impurity profile under a good control.

Abstract: A MOS structure is formed on a silicon semiconductor substrate surface using a first gate electrode film made of polysilicon, an element isolation groove reaching the inside of the silicon semiconductor substrate is formed, and an insulating film is filled in the groove. In addition, a second gate electrode film made of a refractory metal such as molybdenum silicide is formed to be connected to the first gate electrode film, and the first and second gate electrode films are simultaneously removed to form a MOS gate electrode and a wiring layer.

Abstract: A method of forming an MOS capacitor by the steps of cutting a groove in the surface of a silicon substrate by the RIE process, thermally oxidizing the surface of said silicon substrate, depositing a capacitor electrode on said capacitor-insulating layer, being characterized in that when the capacitor-insulating layer is deposited, the surface of the silicon substrate is thermally oxidized in an oxidizing atmosphere containing 15% by vol. of steam.