| 摘要 |
PURPOSE:To shorten test treatment time and decrease the floating of a buried layer by a method wherein windows are opened at an epitaxial layer, polycrystals are filled into the window, a separated region is formed in a diffused manner by utilizing the rapid diffusion speed of the polycrystals when the epitaxial layer is grown by diffusion on a semiconducdor substrate with the buried layer and the separated layer is provided at the epitaxial layer. CONSTITUTION:An n<+> type buried layer 16 is provided at a p type Si substrate 2 in a diffused manner, an n type layer 4 is grown on the whole surface containing the layer 16 in an epitaxial manner, the whole surface is coated with an SiO2 film 10, while windows 14 and 12 are each bored corresponding to a separated region and a base region. The whole surface is coated with a resist film 18, exposing only the window 14, the window 12 is closed, a hole section 16, a bottom surface 16a thereof stays in the layer 4, is formed at the layer 4 in the window 14 by means of etching, and the hole section is filled with polycrystal Si 20. The film 18 is removed together with polycrystal Si 20' coated on the film 18, while the p type impurities are diffused into the exposing window 14, and a p type separated region 24 reaching the substrate 2 is made up in the layer 4 through the polycrystal Si 20. At the same time, a p type base region 22 is formed into the layer 4 through the window 12. |
