| 摘要 |
PURPOSE:To insulate and isolate a semiconductor device in high integration without deterioration of a withstand strength by forming at least one of single crystal insular regions formed through an insulating film on a semiconductor supporting region in a pyramid shape at the bottom on the surface of the supporting region. CONSTITUTION:N type Si single crystal islands 20, 21 are formed by anisotropically etching through an SiO2 film 4 to expose one main surface of a polysilicon region 1. In this case, the widths W of a low withstand island 21 and a high withstand island 20 depend upon the etching speed of the crystal surface, angles between the prescribed surface and the edges, the surfaces, the width of the window of the mask, the width of a frame, and the depth of the island, and the islands 20, 21 can be readily formed by devising the mask. The island 20 has its depth Z1=50mum, twelve polygonal pyramid of the bottom surface A so that the surfaces A and B are (100) plane, the sides are (111) at C1 and (313) at C2. The island 21 has Z2=17mum, eight polygonal pyramid of the bottom surface A so that the surface a is (100) plane, and the all sides are (313). P type layers 22, 23 are formed in the islands. Since the plane (313) for surrounding the island 21 has approx. 5 times of the boundary charge to (100), the withstand strength is not deteriorated even if the potential of the region 1 becomes lower than that of the island 21, thereby obraining a high integration insulated and isolated device. |
