| 摘要 |
PURPOSE:To reduce the effective area of a base, and to prevent a defective insulating film by a method wherein an excellent insulating film is formed on the whole surface, an emitter contact window and a base contact window are bored to the insulating film, polysilicon is buried to the base contact window and a base electrode is formed on the polysilicon. CONSTITUTION:A field oxide film 41 in an n<-> type epitaxial layer 40 is oxidized selectively, an silicon dioxide film is formed, and an SiO2 film 42 is shaped. An Si3N4 film 43 and the SiO2 film 42 are patterned, and an emitter contact window 44 and a base contact window 45 are bored. Non-doped polysilicon is buried in the contact windows 44, 45. Only a surface oxide film 49 and the polysilicon 50 in the emitter contact window are removed selectively, and the emitter contact window 44 is bored again. An electrode window is bored to the SiO2 film 49 on the polysilicon 47 in the base contact window, and an alloy such as an aluminum silicon alloy is applied on the whole surface in a sputtering manner and patterned to form an emitter electrode 53 and a base electrode 54. |
