| 摘要 |
PROBLEM TO BE SOLVED: To provide a field-effect transistor that has a channel length of 1 μm or less, operates in normally-off for 10 years or longer, has an on current of 100 A or more per occupation area of 1 cmof channel region, and can be used as a power semiconductor using an oxide semiconductor in a channel layer.SOLUTION: A negative voltage is applied to a channel layer 4 by charging a floating gate 8, surrounded by insulator films 7, 9 having a thickness of 15 nm or more, with negative charges of an appropriate density. A depletion layer region is thereby formed in the channel layer 4 when the potential of a gate electrode 1 is 0 V, and normally-off operation can be achieved. Since a negative voltage from the floating gate 8 does not degrade the transistor characteristics, e.g., the mobility, a field-effect transistor having a high on current and a low off current for 10 years or longer is obtained. |
