| 摘要 |
PURPOSE:To secure breakdown strength in the reverse direction by providing low impurity concentration which is determined by the desired breakdown strength in the reverse direction in a region into which carriers flow from an emitter electrode through a channel, forming a direct junction between said region and a reverse conductivity type collector layer, extending the collector layer to the surface at the opposite side, and providing a planar structure. CONSTITUTION:A low impurity concentration N-type Si substrate 2 corresponding to expected withstand voltage is used. A P<+> layer 1 is formed by impurity diffusion from one surface. A P<+> layer 11 is formed at a peripheral part other than an area based on the current capacity of an element by impurity diffusion using a mask from the other surface. Then, a P<+> layer 32 is thinly formed on the surface layer of the N<-> layer 2 at the lower parts of parts where an emitter layer and a channel layer are formed. An N<-> layer 20 is further laminated on said substrate. Thereafter, a P<+> layer 31 which reaches the P<+> layer 32 and whose lateral expansion is smaller and a P<+> layer 12 reaching the P<+> layer 11 are formed at the same time by impurity diffusion. A P-channel layer 3 is formed on the surface part. An N<+> emitter layer 4 is formed on a part of the layer 3. Thus the desired value of breakdown strength can be obtained. |
