| 摘要 |
PURPOSE:To unify surface concentration of impurity region and improve yield productivity by forming an oxide film at the surface, extending impurity region in a substrate under the nitrogen ambient and thereby executing thermal oxidation and slumping process. CONSTITUTION:The P type impurity is implanted to a semiconductor substrate 11 allowing formation of the N<-> layer 10 at the surface region and a high concentration impurity diffusion source layer 12 is formed. It is oxidized under the dry oxygen ambient of 1,000-1,100 deg.C and an oxide film 13 is formed on the impurity diffusion source layer 12 and rear surface of semiconductor substrate 11. Thereafter, it is then subjected to the slumping process for several hours under the nitrogen ambient at a temperature of 1,000 deg.C and thereby the impurity region 14 is formed by the impurity diffusion of impurity diffusion source layer 12. The thermal oxidation is executed under the oxidation ambient and a thermal oxide film 15 is formed integrally on an oxide film 13. Thereafter, the slumping process is executed again at 1,200-1,300 deg.C and thereby the base layer 16 is formed in the N<-> layer 10. |
