| 摘要 |
PURPOSE:To perform a diffusion only in the prescribed region of a semiconductor by covering the surface of a semiconductor polycrystalline layer with a silicon oxidized film, forming an impurity source layer on the film, selectively removing an unnecessary part and diffusing the impurity in a substrate from the remaining impurity source layer through the oxidized film and the polycrystalline layer into the substrate under them. CONSTITUTION:A P-type base region 4 and a resistance layer 5 are diffused and formed on the surface of an N-type Si layer 2, holes 8-11 are opened at an SiO2 film 6 covered on the surface of the layer 2, and a polycrystalline Si layer 12 is accumulated on the overall surface of the layer 2. In this state so far is the ordinary method, but it is then oxidized to alter only the surface layer of the layer 12 into an SiO2 film 21, a PSG layer 13 is grown on the film 21, and the layers 13 of the part which does not require introduction of an N-type impurity such as a hole 10 as a base electrode window and a hole 11 as a resistance electrode window. Thereafter, it is heat treated, P in the layer 13 is diffused through the film 21 and the layer 12 into the holes 8, 9, and an N<+>type collector contact layer 14 and an emitter region 15 are formed. |
