| 摘要 |
PURPOSE:To enable higher breakdown strength by forming a guard ring in dig-in type structure and deepening the depth of the dig-in of the guard ring with separation from a main junction. CONSTITUTION:A surface film 3 composed of an oxide film is formed onto the surface of an N<-> type semiconductor substrate 1, and the surface film 3 on guard rings 4a, 4b, 4c is removed through etching, etc., thus shaping concentric opening windows. The semiconductor substrate 1 is etched through the opening windows, and grooves 2a, 2b, 2c are formed first. Only the groove 2a nearest to a central section is protected by the surface film 3 such as the oxide film, a resist, etc., and the semiconductor substrate 1 is further dug in through etching. No.1 and No.2 guard rings 2a, 2b from the central section are protected by the surface films 3 such as the oxide films, the resists, etc., the semiconductor substrate 1 is further dug in, P<+> type impurity diffusion layers are shaped to the dug-in each groove 2a, 2b, 2c, and the guard rings 4a, 4b, 4c are acquired while a P<+> type impurity diffusion layer 5 is also formed at the central section, thus forming a main junction. |
