| 摘要 |
PROBLEM TO BE SOLVED: To easily provide a transistor having a plurality of threshold voltages on the same substrate, by providing a region where P type impurity ions are implanted and a region where N type impurity ions are implanted on the same gate. SOLUTION: P type impurity ions are implanted in a channel 104, and on a gate electrode, an N type impurity region 108 is provided on the side of a source 102, and a P type impurity region 107 is provided on the side of a drain 103 in this order by ion implantation. The threshold value of a MOS transistor can be changed by changing the ratio of the N type impurity region 109 and the P type impurity region 107 in the channel lengthwise direction. When N type impurity ions are implanted over the entire gate electrode, the threshold voltage reduces, and when P type impurity ions are implanted, it increases. Therefore, the threshold voltage of the MOS transistor can be easily controlled, and the transistor having a plurality of threshold voltages can be easily obtained on the same substrate. |
