Thin film transistor, method of manufacturing the same, and organic light emitting display device including the same
Disclosed are a thin film transistor, a method of manufacturing the same, and an organic light emitting display device including the same, in which a driving stability of a driving transistor is enhanced even without connecting a source electrode to a bottom gate electrode of the driving transistor. The film transistor includes a N-type semiconductor layer, a P-type semiconductor layer on the N-type semiconductor layer, a first gate electrode on the P-type semiconductor layer, a gate insulation layer between the first gate electrode and the P-type semiconductor layer, a first source electrode connected to a first side of the P-type semiconductor layer, and a first drain electrode connected to a second side of the P-type semiconductor layer.
1. A thin film transistor comprising:
an N-type semiconductor layer;
a P-type semiconductor layer on the N-type semiconductor layer;
a first gate electrode over the P-type semiconductor layer;
a gate insulation layer between the first gate electrode and the P-type semiconductor layer;
a first source electrode connected to a first side of the P-type semiconductor layer; and
a first drain electrode connected to a second side of the P-type semiconductor layer.
2. The thin film transistor of claim 1 , wherein when, a threshold voltage of the N-type semiconductor layer satisfies where
Vth
N
1
>
DV
2
,
Vth N1 is the threshold voltage of the N-type semiconductor layer is and DV is a drain voltage applied to the first drain electrode.
3. The thin film transistor of claim 1 , wherein
the first source electrode includes a first source electrode layer contacting the P-type semiconductor layer and having a P-type semiconductor characteristic, and a second source electrode layer disposed on the first source electrode layer, and
the first drain electrode includes a first drain electrode layer contacting the P-type semiconductor layer and having the P-type semiconductor characteristic, and a second drain electrode layer disposed on the first drain electrode layer.
4. The thin film transistor of claim 3 , wherein the P-type semiconductor layer, the first source electrode layer, and the first drain electrode layer are formed of the same material.
5. The thin film transistor of claim 1 , wherein the P-type semiconductor layer has a thickness thinner than a thickness of the N-type semiconductor layer.
6. The thin film transistor of claim 1 , wherein the N-type semiconductor layer is an N-type oxide semiconductor layer, and the P-type semiconductor layer is a P-type oxide semiconductor layer.
7. The thin film transistor of claim 6 , wherein the P-type semiconductor layer includes Cu 2 O.
8. A method of manufacturing a thin film transistor, the method comprising:
forming a first N-type semiconductor layer and a P-type semiconductor layer of a first thin film transistor and a second N-type semiconductor layer of a second thin film transistor, on a first gate insulation layer;
forming a second gate insulation layer on the P-type semiconductor layer and forming the second gate insulation on the second N-type semiconductor layer;
forming a first gate electrode overlapping the P-type semiconductor layer on the second gate insulation layer and a second gate electrode overlapping the second N-type semiconductor layer on the second gate insulation layer;
forming an interlayer dielectric on the first gate electrode and the second gate electrode;
forming first and second contact holes exposing a portion of the P-type semiconductor layer to pass through the interlayer dielectric, and third and fourth contact holes exposing a portion of the second N-type semiconductor layer; and
forming a first source electrode connected to the P-type semiconductor layer through the first contact hole, a first drain electrode connected to the P-type semiconductor layer through the second contact hole, a second source electrode connected to the second N-type semiconductor layer through the third contact hole, and a second drain electrode connected to the second N-type semiconductor layer through the fourth contact hole, on the interlayer dielectric.
9. The method of claim 8 , wherein a threshold voltage of the first N-type semiconductor layer satisfies
Vth
N
1
>
DV
2
,
where Vth N1 is the threshold voltage of the first N-type semiconductor layer and DV is a drain voltage applied to the first drain electrode.
10. The method of claim 8 , wherein the P-type semiconductor layer has a thickness thinner than a thickness of the first N-type semiconductor layer.
11. The method of claim 8 , wherein the first N-type semiconductor layer and the second N-type semiconductor layer are an N-type oxide semiconductor layer, and the P-type semiconductor layer is a P-type oxide semiconductor layer.
12. The thin film transistor of claim 11 , wherein the P-type semiconductor layer includes Cu 2 O.
13. An organic light emitting display device comprising:
a pixel including an organic light emitting diode, a first thin film transistor, and a second thin film transistor, and connected to a scan line and a data line,
wherein the first thin film transistor has a first N-type semiconductor layer and a P-type semiconductor layer is disposed on the first N-type semiconductor layer, and the second thin film transistor has a second N-type semiconductor layer.
14. The organic light emitting display device of claim 13 , wherein a threshold voltage of the first N-type semiconductor layer satisfies
Vth
N
1
>
DV
2
,
where Vth N1 is a threshold voltage of the first N-type semiconductor layer and DV is a source voltage.
15. The organic light emitting display device of claim 13 , wherein the first thin film transistor further comprises:
a first gate electrode on the P-type semiconductor layer;
a gate insulation layer between the first gate electrode and the P-type semiconductor layer;
a first source electrode connected to a first side of the P-type semiconductor layer; and
a first drain electrode connected to a second side of the P-type semiconductor layer.
16. The organic light emitting display device of claim 15 , wherein
each of the first and second source electrodes comprises a first source electrode layer contacting the P-type semiconductor layer and having a P-type semiconductor characteristic, and a second source electrode layer disposed on the first source electrode layer, and
each of the first and second drain electrodes comprises a first drain electrode layer contacting the P-type semiconductor layer and having the P-type semiconductor characteristic, and a second drain electrode layer disposed on the first drain electrode layer.
17. The organic light emitting display device of claim 16 , wherein the P-type semiconductor layer, the first source electrode layer, and the first drain electrode layer are formed of the same material.
18. The organic light emitting display device of claim 13 , wherein a thickness of the P-type semiconductor layer is thinner than a thickness of the first N-type semiconductor layer.
19. The organic light emitting display device of claim 13 , wherein each of the first and second N-type semiconductor layers is an N-type oxide semiconductor layer, and the first P-type semiconductor layer is a P-type oxide semiconductor layer.
20. The organic light emitting display device of claim 19 , wherein the P-type semiconductor layer includes Cu 2 O.