| 摘要 |
PURPOSE:To simplify the manufacturing process of semiconductor device, carrying out heat treatment and diffusion of polycrystalline silicon in one and the same step as well as to prevent the raise of a breakdown voltage caused by a deep diffusion layer, by forming an impurity diffusion layer in a deepness in conformity with a design value. CONSTITUTION:An oxide film 11 formed on the surface of a semiconductor substrate 1 is subjected to photoetching to form holes 12 at the points opposed to the regions to be provided with guard rings 2. The rings 2 are formed by diffusion and the film 11 surrounding the rings 2 is removed. Another oxide film 13 is formed on the surface of the oxide film 4 for photoetching, and is passivated to form a film 14. A polycrystalline silicon film 5 is formed by CVD to cover from the region to be provided with a diffusion layer 3 to the surface of the film 13. Then the outer periphery of the film 5 is removed by photoetching, and the film 5 is heat treated to cause impurities to diffuse into the surface of the substrate. Thus the diffusion layer 3 can be formed during the heat treatment of the film, whereby the manufacturing process of semiconductor devices can be simplified. |
