| 摘要 |
PURPOSE:To enable to effectively prevent a latchup phenomenon by electrically insulating and isolating a well region via an SiO2 layer, thereby eliminating the production of a parasitic bipolar transistor structure. CONSTITUTION:An SiO2 layer 6 is formed on an N type semiconductor substrate 1, an N type epitaxial layer 7 is grown, and an SiO2 film 8 and SiO3N4 film 9 are formed. The first film 11 and the second film 12 remain by selective etching. The layer 7 is formed as an SiO2 layer 13 by oxidizing, and the insulated and isolated remaining epitaxial layer 7 is formed under the first film 11. Boron ions are implanted as a P type well region 14, the seource and drain region 15 of an N type MOS transistor, and the source and drain region 16 of a P type MOS transistor are formed, and gate insulating films 17, 18 and gate electrodes 19, 20 are formed. |
