METHOD FOR MANUFACTURING A SEMICONDUCTOR DEVICE

摘要

An oxide layer is partially formed on an n-type region surrounded by a field oxide region. A base region of a switching transistor is formed in the n-type region using as a mask the oxide layer. Arsenic-doped polysilicon layers are selectively formed simultaneously on the surfaces of the oxide layer and the base region. Using the polysilicon layers as a mask, the emitter and collector regions of an injector transistor and the external base region of a switching transistor are formed in the n-type region and the base region respectively. Arsenic doped into the polysilicon layers is diffused into the base region, so that the collector regions of the switching transistor are self-aligned with the polysilicon layers.