| 摘要 |
PURPOSE: To improve hot carrier withstand voltage by making virtually equal the dimensions in the direction of gate length of the semiconductor regions of low impurity concentration, which form the LDD structure of a first and a second MISFETs, respectively. CONSTITUTION: The n-channel MISFETs Qn of an input/output stage circuit and an internal circuit are composed of a gate insulating film 26, a gate electrode 27, a n-type semiconductor region 29, and a n--type semiconductor region 32, respectively. The side wall spacers 31 of these n-channel MISFETs Qn are virtually the same in size in the direction of gate length. The gate length of the n-channel MISFET Qn in the input/output stage circuit is made larger than that of the n-channel MISFET Qn in the internal circuit. Further, the n-type semiconductor regions 29 forming the LDD structure of the n-channel MISFETs are virtually the same in size in the direction of gate length. This improves hot carrier withstand voltage, and reduces threshold voltage drop with a lapse of time, which enables the improvement of electrical characteristics. |
