| 摘要 |
PURPOSE:To reduce number of manufacturing processes by making a semiconductor substrate and the other part electrically separated from each other by providing an island type semiconductor area with the shape of closed bottom, inverted truncated cone. CONSTITUTION:From a thin buffer layer 86 of silicon oxide to prevent the unnecessary distorsion between a semiconductor substrate 71 and a masking layer 85 on the main surface 72 of the semiconductor substrate 71 of N type silicon. On them is formed the masking layer 85 with an opening 84 of polycrystalline silicon shaped like an inverted truncated cone. Then, by ion injection treatment an insulating layer 73 of the shape of closed bottom, inverted truncated cone is produced to form an island-shaped semiconductor area 74, surrounded with above cone. The masking layer 85 and the buffer layer 86 are removed from the semiconductor substrate 71. The island-shaped semiconductor area 74 can be manufactured by a general process of desired MIS electric field effect transistor. |
