Thin film transistor, method for manufacturing the same and display device comprising the same
A thin film transistor is disclosed, which includes an oxide semiconductor layer on a substrate; a gate insulating film on the oxide semiconductor layer; a gate electrode on the gate insulating film; a hydrogen supply layer on the gate insulating film; a source electrode connected with the oxide semiconductor layer; and a drain electrode spaced apart from the source electrode and connected with the oxide semiconductor layer, wherein the oxide semiconductor layer includes a channel portion overlapped with the gate electrode and a connecting portion not overlapped with the gate electrode, a hydrogen concentration of the connecting portion is higher than that of the channel portion, and the gate insulating film includes a first area overlapped with the gate electrode and a second area not overlapped with the gate electrode, and a hydrogen concentration of the second area is higher that of the first area.
1. A thin film transistor comprising:
an oxide semiconductor layer on a substrate;
a gate insulating film on the oxide semiconductor layer;
a gate electrode on the gate insulating film;
a hydrogen supply layer on the gate insulating film;
a source electrode connected with the oxide semiconductor layer; and
a drain electrode spaced apart from the source electrode and connected with the oxide semiconductor layer,
wherein the oxide semiconductor layer includes a channel portion overlapped with the gate electrode and a connecting portion not overlapped with the gate electrode, a hydrogen concentration of the connecting portion is higher than that of the channel portion, and the gate insulating film includes a first area overlapped with the gate electrode and a second area not overlapped with the gate electrode, and a hydrogen concentration of the second area is higher that of the first area
wherein, for the hydrogen supply layer, a hydrogen concentration of the area overlapped with the gate electrode is higher than that of the area not overlapped with the gate electrode.
2. The thin film transistor according to claim 1 , wherein the connecting portion has a gradient of a hydrogen concentration along a direction of the hydrogen supply layer from the substrate.
3. The thin film transistor according to claim 1 , wherein the connecting portion has a hydrogen concentration of approximately 3 atom % to 6 approximately atom %.
4. The thin film transistor according to claim 1 , wherein the gate insulating film is disposed on an entire surface of the oxide semiconductor layer in an opposite direction of the substrate.
5. The thin film transistor according to claim 1 , wherein the second area of the gate insulating film has a gradient of a hydrogen concentration along a thickness direction.
6. The thin film transistor according to claim 1 , wherein a hydrogen concentration of the second area increases in a direction toward the hydrogen supply layer from the substrate.
7. The thin film transistor according to claim 1 , wherein the hydrogen supply layer is extended to an upper portion of the gate electrode.
8. The thin film transistor according to claim 1 , wherein the hydrogen supply layer has a thickness of approximately 2 nm to approximately 10 nm.
9. The thin film transistor according to claim 1 , wherein the hydrogen supply layer is formed of a silicon nitride.
10. The thin film transistor according to claim 1 , wherein a conductivity of the connecting portion is higher than that of the channel portion based on the connecting portion having the higher hydrogen concentration than that of the channel portion.