| 摘要 |
PURPOSE:To enable to stabilize the threshold voltage by a method wherein the second impurity region of the same conductivity type a that of the semiconductor substrate is formed in the first semiconductor region by leaving an insulation film only on the side surface of a poly Si gate electrode. CONSTITUTION:The zero impurity region 3 of the conductivity type reverse to that of the substrate 1 and a gate oxide film 5 are formed. The poly Si gate electrodes 6a and 6b are formed, the first impurity region 7 of the condutivity type reverse to that of the substrate 1 is formed with said electrodes as a mask, and the insulation film 12 is grown and etched. Since this sputter etching has the ratio of vertical and transversal etching at several ten or more, the insulation films 12a and 12b on the side surface of the poly Si's remain. When the second impurity region 8 of the same conductivity type as that of the substrate 1 is formed with said electrodes 6a and 6b and insulation films 12a and 12b as a mask, the diffusion positions of the first impurity region 7 and the second one 8 become B and C, respectively, resulting in slippage by the thickness (t) of the insulation film. Therefore, the part of gentle profile of said region 7 intersects the second one 8, and accordingly the threshold voltage stabilizes. |
