| 摘要 |
PURPOSE:To increase the integration density and to obtain a device that is suitable for high frequencies by providing a second electrical insulation layer at the periphery of a polycrystal silicon layer, and connecting a portion of electrode to the polycrystal silicond layer by way of a U-shaped insulating layer. CONSTITUTION:An SiO2 film 5 with a specified thickness is formed on a semiconductor substrate 4, an opening, in which an emitter region is to be formed, is provided, and a polycrystal silicon layer 12 with a specified thickness is formed by doping As in a high-frequency heating furnace containing silane and arsine. Then, the layer 12 is patterned by plasma etching. Thereafter, an emitter diffusion layer 15 is formed by heating in an oxidized atmosphere, and an SiO2 layer 15 is formed on the exposed portion of the layer 12. Photoetching is made on the layer 15, thereby an opening 15a is provided. Then, an electrode 11 in a specified shape is formed by evaporation of a wiring-metal layer so that its edge portion is not directly contacted with the layer 12, thereby abnormal etching phenomena are prevented and the high-integration density can be achieved.
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