| 摘要 |
PURPOSE:To enhance the density of an element, to reduce the leakage current between elements and to improve the withstand voltage of a drain in an MOS type semiconductor device by forming source and drain regions in two isolated substrates surrounded by an insulating layer shallower than the lower surface of the insulating layer. CONSTITUTION:An element isolating region 17 is formed on a p type Si substrate 11, and an n type impurity such as phosphorus or arsenic ions are implanted to form an n<+> type impurity layer 19 to become source and drain regions. An SiO2 film 20 is formed, a groove 23 is formed by etching, a resist pattern 22 and the film 20 are removed, a thermally oxidized film 24 is formed by thermally oxidizing, and a polycrystalline silicon layer 25 is formed. Then, the impurity in the layer 19 is diffused by heat treating to the position not reaching the lower surface 27 of the region 17 but deeper than the lower surface 26 of the groove 23 as source and drain regions 30, 31, the layer 25 and the film 24 are removed, and an MOS type semiconductor device is obtained. |
