| 摘要 |
PURPOSE:To obtain the second transistor (Tr) having high withstand voltage at a semiconductor device by a method wherein a part of the opening parts to form the first Tr in an insulating film on a substrate is covered with a protective film, and after the semiconductor region for the second Tr is formed, the protective film is removed, and the first and the second Tr's are formed at the same time. CONSTITUTION:An N type epitaxial layer 3 is formed on the substrate 1 interposing N<+> type buried layers 2 between them, and an oxide film 11 having openings at the parts to constitute the base regions and the integrated injection logic I<2>L is formed. The part to constitute the base region for the I<2>L part is covered with the protective film 13, and the base region 8, the injector region 5 are formed at the same time from the other openings. Then the protective film 13 is removed, and the injector region 5' and the base regions 6, 8' are formed at the same time. The base region 6 of the I<2>L part has low concentration, and the base region 8' of the Tr at the analog IC part has high concentration and is doped deeply. Accordingly the I<2>L having high current amplification factor and the analog IC having high withstand voltage can be formed at the same time. |
