| 摘要 |
PURPOSE:To suppress leak currents that may be generated between a source and drain and thereby to improve the radiation-withstanding capability by a method wherein an insulating film just under a gate electrode end is formed as thin as the gate insulating film and the substrate surface just under the thin insulating film is converted into a P-region. CONSTITUTION:A field oxide film 2 is formed by selective oxidation on a P-type silicon substrate 1, and a gate insulating film 3 is formed by dry oxidation in a region to be an element region. After diffusion of phosphorous into a polycrystalline silicon film to be formed by vapor phase growth on the entire surface of the oxide film, patterning is accomplished for the formation of a gate electrode 4. The gate electrode 4 serves as a mask in a process of impurity ions implantation for the formation of an N<+>-type source region 5 and drain region 6. A low-concentration P<->-type region 7 is formed to extend from under an insulating film 3' under an end of the gate electrode 4 to extend to the outside of the source and drain regions 5 and 6, and a guard band 8 is formed.
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