Organic thin film transistor having circular organic semiconductor layer and flat panel display including the same

1. An organic thin film transistor comprising:

a gate electrode;

source and drain electrodes insulated from the gate electrode; and

an organic semiconductor layer insulated from the gate electrode and contacting the source and drain electrodes, wherein the organic semiconductor layer has a circular shape when viewed through a substrate on which the organic thin film transistor is formed, and edge portions of both the source and drain electrodes contacting the organic semiconductor layer have curved shapes that are concave toward the organic semiconductor layer.

2. The organic thin film transistor of claim 1 , wherein the gate electrode has a circular shape when viewed through a substrate on which the organic thin film transistor is formed.

3. The organic thin film transistor of claim 1 , wherein the length of an edge portion of the source electrode contacting the organic semiconductor layer and facing the drain electrode is greater than the length of an edge portion of the drain electrode contacting the organic semiconductor layer and facing the source electrode.

4. The organic thin film transistor of claim 1 further comprising a gate insulating layer insulating the source and drain electrodes and the organic semiconductor layer from the gate electrode.

5. The organic thin film transistor of claim 4 , wherein the gate insulating layer is formed on the gate electrode to cover the gate electrode, the source and drain electrodes are formed on the gate insulating layer, and the organic semiconductor layer is formed on the source and drain electrodes and the gate insulating layer.

6. The organic thin film transistor of claim 4 , wherein the organic semiconductor layer is formed on and between the source and drain electrodes, the gate insulating layer is formed on the organic semiconductor layer to cover the organic semiconductor layer and the source and drain electrodes, and the gate electrode is formed on the gate insulating layer.

7. A flat panel display comprising at least one organic thin film transistor comprising:

a gate electrode;

source and drain electrodes insulated from the gate electrode;

an organic semiconductor layer insulated from the gate electrode and contacting the source and drain electrodes, wherein the organic semiconductor layer has a circular shape when viewed through a substrate on which the organic thin film transistor is formed, and an edge portion of at least one of the source and drain electrodes contacting the organic semiconductor layer has a curved shape that is concave toward the organic semiconductor layer; and

a channel region between the source and drain electrodes, wherein distance between the source and drain electrodes varies across the channel region.

8. A flat panel display comprising at least one organic thin film transistor comprising:

a gate electrode;

source and drain electrodes insulated from the gate electrode; and

an organic semiconductor layer insulated from the gate electrode and contacting the source and drain electrodes, wherein the organic semiconductor layer has a circular shape when viewed through a substrate on which the organic thin film transistor is formed, and an edge portion of at least one of the source and drain electrodes contacting the organic semiconductor layer has a curved shape that is concave toward the organic semiconductor layer, wherein edge portions of both the source and drain electrodes contacting the organic semiconductor layer have curved shapes that are concave toward the organic semiconductor layer.

9. An organic thin film transistor comprising:

a gate electrode;

source and drain electrodes insulated from the gate electrode;

an organic semiconductor layer insulated from the gate electrode and contacting the source and drain electrodes, wherein the organic semiconductor layer has a circular shape when viewed through a substrate on which the organic thin film transistor is formed, and an edge portion of at least one of the source and drain electrodes contacting the organic semiconductor layer has a curved shape that is concave toward the organic semiconductor layer; and

a channel region between the source and drain electrodes, wherein distance between the source and drain electrodes varies across the channel region.

10. The organic thin film transistor of claim 9 , wherein the gate electrode has a circular shape when viewed through a substrate on which the organic thin film transistor is formed.

11. The organic thin film transistor of claim 9 , wherein the length of an edge portion of the source electrode contacting the organic semiconductor layer and facing the drain electrode is greater than the length of an edge portion of the drain electrode contacting the organic semiconductor layer and facing the source electrode.

12. The organic thin film transistor of claim 9 further comprising a gate insulating layer insulating the source and drain electrodes and the organic semiconductor layer from the gate electrode.

13. The organic thin film transistor of claim 12 , wherein the gate insulating layer is formed on the gate electrode to cover the gate electrode, the source and drain electrodes are formed on the gate insulating layer, and the organic semiconductor layer is formed on the source and drain electrodes and the gate insulating layer.

14. The organic thin film transistor of claim 12 , wherein the organic semiconductor layer is formed on and between the source and drain electrodes, the gate insulating layer is formed on the organic semiconductor layer to cover the organic semiconductor layer and the source and drain electrodes, and the gate electrode is formed on the gate insulating layer.