| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a transistor having stable electric characteristics with light degradation suppressed as much as possible, and a semiconductor device including the transistor. <P>SOLUTION: A transistor comprises: an oxide semiconductor layer; a source electrode layer and a drain electrode layer that overlap with a part of the oxide semiconductor layer; a gate insulation layer that overlaps with the oxide semiconductor layer, the source electrode layer and the drain electrode layer; and a gate electrode that overlaps with a part of the oxide semiconductor layer via the gate insulation layer. The transistor exhibits two kinds of modes in which the carrier relaxation time is at least τ<SB POS="POST">1</SB>and τ<SB POS="POST">2</SB>in a light response characteristic when the oxide semiconductor layer serving as a channel formation region is irradiated with light and then the light is blocked. The modes satisfy τ<SB POS="POST">1</SB><τ<SB POS="POST">2</SB>, where τ<SB POS="POST">2</SB>is 300 seconds or less. A semiconductor device comprises the transistor. <P>COPYRIGHT: (C)2012,JPO&INPIT |
