Method of manufacturing a bipolar transistor

摘要

In a semiconductor apparatus having a PNP bipolar transistor and high voltage resistance, there is formed an oxide insulating layer in the surface region of a P-type semiconductor substrate. In the above semiconductor substrate is formed a P-type collector layer so that at least a part of the P-type collector layer is in contact with said oxide insulating layer. In the surface region of said P-type collector layer is formed a P-type collector contact layer. An N-type base layer is formed in that region on the surface side of said P-type collector layer in which said P-type collector contact layer does not exist. A P-type emitter layer is formed on the surface side of said N-type base layer. A P-type collector-contact/base leakage prevention layer, which has a higher impurity concentration than said P-type collector layer, is formed at least in that region of said P-type collector layer which is in contact with said oxide insulating layer, so as to prevent the generation of a leakage current between said P-type collector contact layer and said N-type base layer.