| 摘要 |
PURPOSE:To predetermine a gate threshold voltage at an optionally required value with good controllability by a method wherein 2nd gate layer is composed of a semiconductor which has a work function different from the work function of a semiconductor of which a channel forming region is composed. CONSTITUTION:A source region 1, a drain region 2, a channel forming region 3 which is formed so as to be contacted with the source region 1 and the drain region 2 and composed of 1st semiconductor and 1st and 2nd gate layers 4 and 5 formed on the channel forming region 3 are provided. The 1st gate layer 4 which is contacted with the channel forming region 3 is composed of 2nd semiconductor which has a wider band gap and lower impurity concentration than the 1st semiconductor and the 2nd gate layer 5 is composed of a semiconductor which has. lower resistance than the material of the 1st gate layer 4 or a higher impurity concentration than the 1st semiconductor. In such a.field effect transistor, the 2nd gate layer 5 is composed of a semiconductor which has a work function different from the work function of the 1st semiconductor. |
