SEMICONDUCTOR DEVICE AND ITS MANUFACTURING METHOD

摘要

A method of manufacturing a semiconductor device in which an N-type semiconductor region having a lowered resistance is formed by irradiating the N-type semiconductor substrate with ions of small mass and then performing a heat treatment, and a semiconductor device having a buffer layer formed by applying such a method to the formation are disclosed. The semiconductor device comprises an N-type semiconductor substrate, a P-type layer formed in one side of the semiconductor substrate, an N<+> layer formed in the other side, and a buffer layer formed near the N<+> layer. The resistance of the buffer layer is between those of the semiconductor substrate and the N<+> layer. By the manufacturing method, a layer having a desired resistance can be formed at a desired depth in a semiconductor substrate without being influenced by the heat treatment after the ion implantation of ions of predetermined conductivity type.