| 摘要 |
PURPOSE:To improve the electric withstand voltage of an oxide film as well as to prevent the fluctuation of threshold voltage of the titled semiconductor device by a method wherein the surface of the oxide film is converted into a nitride film by performing an annealing in ammonia gas on the oxide film located on a semiconductor substrate and then a gate oxide film is grown thereon. CONSTITUTION:A diffusion layer 23 for a guard ring, a diffusion layer 24 for a protective resistor, a source region diffusion layer 25 and a drain region diffusion layer 26 are formed on the surface of a semiconductor substrate 21 by performing a patterning on the field oxide film 22 located on the semiconductor substrate 21, and then an oxide film 27 is formed on the above diffusion layers. Then, while maintaining the above-mentioned condition, the oxide films 22 and 27 are annealed in ammonia gas at 1,000-1,100 deg.C, and the surface part of said oxide films are converted to a nitride film. A gate oxide film 29 is formed on the surface of the semiconductor substrate 21 using an ordinary method, metal wirings 34, 35, 36 and 37 are formed on the oxide films 22 and 27 and, at the same time, a metal gate electrode 38 is formed on the gate oxide film 29. |
