| 摘要 |
PURPOSE:To equalize a distance between a control electrode region and an element isolation region with high accuracy by forming a semiconductor having the same conduction type as the control electrode region and the element isolation region while a mask material having predetermined length shaped so as to be positioned between the control electrode region and the element isolation region consisting of a semiconductor having the same conduction type formed into the same substrate is used as a mask. CONSTITUTION:An oxide film 5 is formed, and BSG (boron silicate glass-that is, an SiO2 film containing B as an impurity) is shaped through a CVD method as a diffusion source, and pushed in, thus forming a p<+> element isolation region 6. An oxide film 7 is removed selectively through etching in order to shape a base region, and an oxide film 8 for buffer is formed in the removed section. B<+> ions or BF2<+> ions generated while employing BF3 as a material gas are implanted to a wafer. The oxide film 7 functions as a mask at that time, and B<+> ions are implanted only under the oxide film 8. When ions are implanted, a p type base region 9 is shaped up to prescribed depth through thermal diffusion. Accordingly, when the element isolation region 6 and the base region 9 are formed, the oxide films 7 and 8 are removed, and an oxide film 10 in thickness of several dozen - several hundreds Angstrom is formed. |
