Abstract: A thin-film transistor includes: an oxide semiconductor layer; an insulating layer formed above the oxide semiconductor layer; and a source electrode and a drain electrode which are located at least partially on the insulating layer and are connected to the oxide semiconductor layer via an opening formed in the insulating layer. The thin-film transistor satisfies a relational expression L1?5.041 exp(5×10?18N), where L1 (?m) is one of protrusion widths of the oxide semiconductor layer in a channel width direction with respect to the source electrode or the drain electrode and N (cm?3) is a carrier density of the oxide semiconductor layer.

Abstract: A thin film semiconductor device comprises a substrate, a gate electrode disposed above the substrate, an oxide semiconductor layer disposed above the substrate so as to oppose the gate electrode, a channel protective layer disposed on the oxide semiconductor layer, and a source electrode and a drain electrode each connected to the oxide semiconductor layer. The density of states DOS [eV?1cm?3] of oxygen defects in the oxide semiconductor layer satisfies the following relationship: DOS?1.710×1017×(Ec?E)2?6.468×1017×(Ec?E)+6.113×1017 provided that 2.0 eV?Ec?E?2.7 eV where Ec [eV] is an energy level of a conduction band edge of the oxide semiconductor layer and E [eV] is a predetermined energy level of the oxide semiconductor layer.

Abstract: A thin film semiconductor device comprises a substrate, a gate electrode disposed above the substrate, an oxide semiconductor layer disposed above the substrate so as to oppose the gate electrode, a channel protective layer disposed on the oxide semiconductor layer, and a source electrode and a drain electrode each connected to the oxide semiconductor layer. The density of states DOS [eV?1cm?3] of oxygen defects in the oxide semiconductor layer satisfies the following relationship: DOS?1.710×1017×(Ec?E)2?6.468×1017×(Ec?E)+6.113×1017 provided that 2.0 eV?Ec?E?2.7 eV where Ec [eV] is an energy level of a conduction band edge of the oxide semiconductor layer and E [eV] is a predetermined energy level of the oxide semiconductor layer.