Patent ID: 6417051
Filing Date: 2002-07-09
Classification: H01L,Y10S

Abstract:
A method of manufacturing a semiconductor device comprising the steps of:(a) forming a buffer silicon oxide film on first and second regions of a semiconductor substrate; (b) selectively removing the buffer silicon oxide film from the first region, and forming a first silicon oxide film on the first region, the first silicon oxide film being thinner than the buffer silicon oxide film; (c) doping nitride atoms into the first silicon oxide film and the buffer silicon oxide film on the second region, and forming a first gate insulating film using the first silicon oxide film containing the nitride atoms; (d) selectively removing the buffer silicon oxide film from the second region and forming a second silicon oxide film on the second region; (e) doping nitride atoms, having a density lower than a density of the nitride atoms of the first gate insulating film, into the second silicon oxide film, and forming a second gate insulating film using the second silicon oxide film containing doped nitride atoms; (f) forming a first gate insulated field effect transistor on the first region; and (g) forming a second gate insulated field effect transistor on the second region.