| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a semiconductor device in which a defect in signal writing to a transistor caused by voltage drop or signal delay due to wiring resistance is prevented, e.g., to provide a display device which achieves high display quality by preventing a defect in grayscale caused by a defect in writing to a transistor provided in a pixel of the display device. <P>SOLUTION: A transistor is manufactured in which wiring including copper with low wiring resistance is connected to a highly purified oxide semiconductor having a wide band gap and a reduced carrier concentration. Use of an oxide semiconductor with a wide band gap enables off-current of a transistor to be reduced. In addition, when such an oxide semiconductor is highly purified and has a reduced carrier concentration, a transistor has a positive threshold voltage. That is, a so-called normally off transistor can be provided to make the ratio between off-current and on-current higher. <P>COPYRIGHT: (C)2013,JPO&INPIT |
