| 摘要 |
PURPOSE:To contrive the improvement in yield of transistors by eliminating an influence of crystal defects produced under bird's beaks by decreasing bird's beaks. CONSTITUTION:An n<+> type buried layer 2 and p<+> type isolation region 11 are formed on a surface of p type Si substrate 1 and an SiO2 layer 12 is formed on the region 11. On the overall surface, an Si layer 13 is epitaxially grown. Polysilicon 14 is produced on the SiO2 layer 12. The surface is oxidized to form the second SiO2 film 15 on which an Si3N4 film 16 is deposited. The film 15 is etched by selective etching using the film 16 as a mask thereby exposing the polysilicon 14. The polysilicon 14 is changed into an SiO2 film 17 by selective oxidation (LOCOS). A collector electrode lead-out hole 7, base 8 and emitter 9 are formed. The SiO2 film formed by LOCOS method has no need of being so thick and a bird's beak becomes remarkably short. |
