| 摘要 |
PROBLEM TO BE SOLVED: To prevent leakage current from increasing at reverse bias of PN junction by forming an insulated gate field effect transistor having an impurity diffused layer as a source-drain region and depositing a thin thermally oxidized silicon on the surface of the impurity diffused layer. SOLUTION: A field oxide film is formed on a silicon substrate 1, a lightly doped source-drain diffusion layer 6 is formed thereon followed by formation of a protective thermal oxide film 7 only on the surface thereof. When a reverse bias is applied between the source-drain diffusion layer 6 and the silicon substrate 1 in such a structure, a first depletion layer 23 is formed on the silicon substrate 1 side and a second depletion layer 24 is formed on the source-drain diffusion layer 6 side. End part 24a of the second depletion layer 24 is located above the end part 22 of the field oxide. Since the surface of the second depletion layer 24 is coated with the protective thermal oxide 7, leakage current through an interface level is prevented. |
