| 摘要 |
PURPOSE:To carry out channel doping without increase of masking process by realizing ion implantation using an Si2N4 film mask in order to form a field SiO2 film. CONSTITUTION:An SiO2 film 6, Si3N4 film 7 and SiO2 film 8 are formed on an Si substrate 13 which will become an n<+> drain region 11. Then, an SiO2 film 16 is formed as a field insulation film with the film 7 used as the mask. Thereafter, the film 7 is over-etched with the film 8 used as the mask. The film 8 is then removed and the film 6 is also etched. Next, p type impurity ion is implanted in view of forming a p<+> gate region 14 and a channel doping region 15. The p type impurity is activated while an oxide film 26 is selectively formed. The films 7, 6 are removed and an n<+> source region 12 is formed. |
