| 摘要 |
PURPOSE:To enable to obtain a steep carrier concentration distribution in an epitaxial layer, by a method wherein a conductive semiconductor layer, being reverse to the epitaxial layer formed on a surface of a substrate, is formed on an embedded region on the substrate. CONSTITUTION:An N<+> type embedded region 2 is selectively formed on a P type Si substrate 1. Then, a very thin P<-> type epitaxial 4 is grown on the substrate. An epitaxial layer 5 on the region 2 is formed into a pi-type layer in terms of a growing condition. A high temperature processing, however, is done, and as a result, diffusion of a donor impurity from a region 2 to a layer 5 is created to control a pi-type growing condition so that the resultant layer 5 forms an N<-> type layer. An N<-> type epitaxial layer 3 is then caused to grow on the layer 4. Said process forms a steep resistivity distribution in the direction of the depth of the layer 3. This prevents the reduction in breakdown voltage in a reverse direction between a transistor base, in which the substrate 1 is formed as a collector, and a collector. |
