| 摘要 |
PURPOSE:To obtain a semiconductor device including a bipolar-transistor having excellent isolation voltage between an emitter and a base and being formed in a self-alignment isolation manner by a method wherein an insulating protective film on a polysilicon layer for leading out a base is shaped in three layer structure, the intermediate layers of the insulating film are side-etched to form voids, the voids are filled with other insulating films to a wedge shape and the shoulder of the end section of the polysilicon layer for leading out the base in the opening section of the emitter is coated with at least two layers. CONSTITUTION:A semiconductor device contains first, second and third insulating protective films 20, 21, 22 and an N-P-N bipolar-transistor in which the end section of the opening section of an emitter, the side wall surface of a polysilicon layer 8 for leading out a base, is coated with an insulating film having three layer structure of an silicon oxide film 23 and silicon nitride films 24, 25. CVD silicon nitride films are used as the first and third insulating protective films 20 and 22 and an silicon oxide film as the second insulating protective film 21 at that time. Voids in the intermediate second insulating protective film 21 side- etched during a manufacturing process are filled with the silicon nitride film 24 through a CVD method. The lower edge of another emitter opening section functioning as the forming window of all emitter region 5 together with the silicon nitride film 25 are coated with the silicon oxide film 23.
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