| 摘要 |
PURPOSE:To prevent a latch-up completely by a method wherein a second conduction type impurity is implanted to the surface of a semiconductor substrate, a buried layer, impurity concentration in the surface thereof is sufficiently lower than the inside, is formed, a first conduction type semiconductor layer is grown, and a second conduction type impurity is implanted to a position on the buried layer to shape a well. CONSTITUTION:A pattern 52 for an oxide film is formed on an n type silicon substrate 51. Boron ions are implanted selectively. Consequently, a high-concentration impurity layer 53 in which the position of a peak in ion implantation is positioned in depth of size such as approximately 5mum is formed to the surface of the substrate 51. The pattern 52 for the oxide film is removed, and an n type silicon single crystal layer 54 is shaped through epitaxial growth only by 1mum thickness. A pattern 55 for a photo-resist is formed, boron ions in low concentration are implanted to the whole surface, boron is diffused from a p-region 56 through heat treatment, and a p-well 57 is formed. A groove 58 reaching to the substrate 51 is shaped selectively to the silicon single crystal layer 54. |
