| 摘要 |
PURPOSE:To improve switching characteristic and an ON voltage between a drain and a source by forming an oxide film on a substrate region of a power MOSFET thicker than a gate oxide film of a channel and the same conductivity type high density as a substrate under the same oxide film. CONSTITUTION:An N<+> type region 10 for suppressing a resistance near the surface of a substrate 5 is formed by ion implanting, a gate oxide film 9 is further formed in a necessary thickness, the region of the film 9 remains, and the other oxide film is removed. Subsequently, after the gate oxide film 1 of the channel and a polysilicon 2 are formed, with the polysilicon 2 as a mask a P-type region 6 and an N<+> type source region 7 are double-diffused. Thereafter, an interlayer insulating film 3 is formed between the polysilicon 2 of a gate electrode and a source electrode 4, a contact window is opened, and a source electrode 4 is formed. Thus, switching characteristic is improved, and an ON voltage between a drain and a source can be improved in high withstanding voltage resistance type. |
