| 摘要 |
PURPOSE:To eliminate the variation of the characteristics of the subject semiconductor device due to an outward diffusion from the reverse side of the substrate by a method wherein, after an oxide film is formed on both sides of the substrate, a nitriding film is formed on its reverse side, a high temperature heat treatment process and then the nitriding film is removed. CONSTITUTION:Oxide films 3 and 4 are formed on the right and reverse sides of the substrate 2, which is an N<+> substrate with an N<-> layer superposed on it, and after a nitriding film 19 is formed on the oxide film 4 of the reverse side, a base region 7 and an emitter region 9 are formed by performing a multiple diffusion. After that, the nitriding film 19 is removed by performing a plasma etching or by using thermal phosphate. And after removing the oxide film 4, electrodes 10, 11 and 12 are formed. The formation instability of the base region 7 and the emitter region 9, due to the outward diffusion of the donor coming from the N<+> substrate when the high temperature heat treatment is performed, is hereby prevented and the semiconductor device for stabilized characteristics can be obtained. |
