Method of manufacturing a biopolar transistor in which an emitter region is formed by impurities supplied from double layered polysilicon

摘要

A process of fabricating a bipolar transistor, particularly forming a very shallow, uniform emitter diffused-layer for the purpose of realizing a higher speed of the device without need of prolongating LSI fabrication term. In the process of building a bipolar transistor on a n- type semiconductor substrate, after forming the p-type base region of the bipolar transistor, an insulating film is formed, in an region of which where an emitter is to be formed a contact hole is opened. In the next processing step, polysilicon films of different arsenic contents are stacked on top of one the other, followed by thermal diffusion of arsenic, to form an emitter region in the base region. The first polysilicon film has a low arsenic content than the second polysilicon film, and a silicon dioxide film of up to 5 nm in thickness is interposed between the polysilicon films.