| 摘要 |
PROBLEM TO BE SOLVED: To provide low threshold voltage, while the drop of withstand voltage owing to the drop of the concentration of a body area and the increase of the concentration of a drift area by means of the diffusion of channel dope impurity is prevented. SOLUTION: A gate insulating film 3 is formed on a first conduction-type semiconductor substrate 1 and a gate electrode 4 is formed on the film. The gate insulating film 3, of a part where the gate electrode 4 is not formed, is etched. Then, a thermal oxide film is formed and second conductivity-type impurity which is a body region 7 is implanted to the source region 5 of a duplex diffusion-type insulating gate field effect transistor. The semiconductor substrate 1 is heat treated. First conductivity-type impurity is implanted to the second conductivity-type body region 7 as channel dope by inclining it from a drain region 6 on the same element by an inclination exceeding 7 degrees in the direction of the source region 5 with respect to a vertical direction from the face of the semiconductor substrate 1. |
