| 摘要 |
PURPOSE:To decrease electric field intensity in a drain depletion layer without decreasing mutual conductance, and decrease the number of generating hot carriers, by forming a low concentration impurity region just under a gate electrode, in the manner in which the length is short on the source side and long on the drain side. CONSTITUTION:On the drain side of a gate electrode 3, a first side wall 4 and a second side wall 5 are formed so as to overlap each other. On the source side, the second side wall only is formed. The source-drain region 6, 7 of a semiconductor substrate 1 is constituted of low concentration impurity regions 6a, 7a and high concentration impurity regions 6b, 7b. In the former, low concentration N-type impurity is introduced. In the latter, high concentration impurity is introduced. On the drain side, the low concentration impurity region 7a is formed to have a long length, so that electric field intensity in a depletion layer of the drain region is decreased, and the generation of hot carrier can be restrained. On the source side, the low concentration impurity region 6a just under the gate electrode 3 is made short, so that channel resistance can be reduced, and the decrease of mutual conductance can be prevented. |
