| 摘要 |
PURPOSE:To inhibit the increase of threshold voltage, and to prevent a punch- through by implanting impurity ions having the same conduction type as a substrate into the substrate and implanting Cs ions into a gate oxide film. CONSTITUTION:A field oxide film 2 and a gate oxide film 3 are formed onto a P type Si substrate 1. Cs ions 5 are implanted into the film 3. A P type impurity 6 is introduced to the surface of the substrate 1 through ion implantation to shape a P type region 7. The layer 7 fills the role of the inhibition of the extension of depletion layers in source-drain regions and the prevention of a punch- through. A gate electrode 8 is formed, and an N type impurity 9 is implanted while using the electrode 8 as a mask, thus forming the source-drain regions 10. According to the structure, the channel of an element can be shortened without augmenting threshold voltage because the increase of threshold voltage induced by the layer 7 is compensated by the positive fixed charges of Cs implanted to the film 3. |
