| 摘要 |
PURPOSE:To shorten a section between an emitter layer and a base electrode window, and to omit an external base in high impurity concentration and to improve frequency characteristics by directly extracting a base electrode from an active base layer through a double layer of poly Si and a metallic silicide. CONSTITUTION:A composite film 205 of SiO2 105, Si3N4 201 and SiO2 201 is formed on an n<-> epitaxial layer 3 through a conventional process, a p layer 6 is formed, the film 205 is removed selectively, the surface is coated with p type poly Si 500, and a p layer 61 is formed through sintering. The poly Si 500 is removed selectively through etching, a window is bored through etching by a resist mask 302, and an emitter and a base extracting layer are brought near. The base electrode window is coated with a mask 303, and n<+> layers 7, 8 are formed. The mask 303 is removed, Ti 600 is evaporated, and a TiSi layer 601 is formed through sintering. Ti 600 is removed through etching, the surface is coated with PSG 401, a resist mask 304 is executed, and electrodes 9- 11 are attached. In the constitution, the frequency characteristics of a transistor obtained are excellent because base resistance can be reduced and the external base is also removed. |
