| 摘要 |
PURPOSE:To obtain a resistance layer having a desired high resistance, by covering a silicon layer II which does not contain impurities on a silicon layer I with a specified pattern which contains impurities, heating the layers, and diffusing the impurities in the layer I into a substrate through the layer II. CONSTITUTION:A silicon dioxide film 2 is formed on all the surface of a P type single-crystal substrate I. Thereafter, a polycrystal silicon layer 3 with a specified pattern containing impurities is formed. Then, a substrate surface 5 is exposed with a resist film having a hole 4 as a mask. After the resist film is removed, a polycrystal silicon film 6 which does not contain impurities is provided on all the surface, and heat treatment is performed in an nitrogen-gas atmosphere. Then, the impurities in the poly-crystal silicon layer 3 is diffused into the substrate 1 through the film 6, thereby an N type semiconductor layer 7 is formed. When the thermal oxidation is performed in a steam atmosphere, the layers 3 and 6 are transformed into silicon dioxide 8, and an N type diffused layer 9 is obtained in the substrate 1. |
