| 摘要 |
PROBLEM TO BE SOLVED: To improve reliability of a drive circuit.SOLUTION: A semiconductor device comprises an oxide semiconductor layer which overlaps a drain electrode layer 405b (and a source electrode layer 405a) in which a second high resistance drain region 432 (or a first high-resistance drain region 431) is formed. By forming the second high-resistance drain region 432, a structure which can change conductivity from the drain electrode layer to the second high-resistance drain region 432 and a channel formation region in a stepwise fashion can be achieved. As a result, when the drain electrode layer 405b is connected to an interconnection for supplying high power supply potential VDD to operate, a constitution in which a local high electric field is not applied even though a high electric field is applied to between the gate electrode layer 401 and the drain electrode layer 405b because the high-resistance drain region serves as a buffer thereby to improve voltage withstanding of a transistor can be achieved. |
