Method for producing an organic thin film transistor and an organic thin film transistor produced by the method
View Patent ↗A method for producing an organic thin film transistor having, on a substrate, a source electrode, a gate electrode, a drain electrode, an insulating layer and an organic semiconductor layer. The method has a step of forming the source electrode and the drain electrode such that one of the source electrode and the drain electrode which is an inner-located electrode has an outer circumference which is circular or polygonal and that the other electrode which is an outer-located electrode has an inner circumference facing the outer circumference of the inner-located electrode, the inner circumference being of a shape which is substantially concentric with the outer circumference of the inner-located electrode. The method also has a step of forming the organic semiconductor layer for connecting the source electrode and the drain electrode to each other by a process of dropping an organic semiconductor material.
1. A method for producing an organic thin film transistor comprising, on a substrate, a source electrode, a gate electrode, a drain electrode, an insulating layer and an organic semiconductor layer, said method comprising:
forming the source electrode and the drain electrode such that one of the source and drain electrodes, which is an inner-located electrode, has an outer circumference which is in the shape of a circle or is in the shape of a polygon and that the other of the source and drain electrodes, which is an outer-located electrode, has an inner circumference facing the outer circumference of the inner-located electrode, the inner circumference being of a shape which is substantially concentric with the outer circumference of the inner-located electrode;
forming the organic semiconductor layer, after forming the source electrode and the drain electrode, so as to connect the source electrode and the drain electrode to each other by a process of dropping an organic semiconductor material;
forming a water repellent layer on the source electrode and the drain electrode formed by the electrode forming step;
forming a protection layer on the substrate with the organic semiconductor layer;
removing the water repellent layer; and
forming a contact hole which pierces through the protection layer.
2. A method according to claim 1 , wherein the dropping process in the organic semiconductor layer forming process is an ink jet process.
3. A method according to claim 1 , wherein one drop is applied in the dropping process.
4. A method according to claim 1 , wherein the inner circumference of the outer-located electrode is of a same shape as that of the outer circumference of the inner-located electrode.
5. The method of claim 1 , wherein the inner-located electrode is positioned nearer to a surface of the substrate than the outer-located electrode as measured along a direction perpendicular to the surface.
6. The method of claim 5 , wherein the outer-located electrode overlaps the inner-located electrode and the surface.
7. The method of claim 6 , wherein the inner-located electrode overlaps the surface.
8. The method of claim 1 , wherein the process of dropping results in the organic semiconductor layer having an even thickness.
9. The method of claim 8 , wherein the process of dropping comprises having a drop of the organic semiconductor material land onto a center of the inner-located electrode and then spread radially to reach the outer-located electrode.
10. The method of claim 9 , wherein the process of dropping results in the organic semiconductor layer being aligned from an outer rim of the outer-located electrode to the center of the inner-located electrode and along a direction of alignment that matches a direction of a channel width of the organic thin film transistor.
11. The method of claim 8 , wherein the process of dropping results in the organic semiconductor layer being aligned along a direction of alignment that matches a direction of a channel width of the organic thin film transistor.
12. The method of claim 1 , wherein the process of dropping results in the organic semiconductor layer being aligned along a direction of alignment that matches a direction of a channel width of the organic thin film transistor.
13. The method of claim 1 , wherein the process of dropping results in the organic semiconductor layer being aligned from an outer rim of the outer-located electrode to the center of the inner-located electrode and along a direction of alignment that matches a direction of a channel width of the organic thin film transistor.
14. A method for producing an organic thin film transistor comprising, on a substrate, a source electrode, a gate electrode, a drain electrode, an insulating layer and an organic semiconductor layer, said method comprising:
forming the gate electrode on the substrate;
forming the insulating layer so as to cover the gate electrode formed on the substrate;
forming the source electrode and the drain electrode on the insulating layer such that one of the source and drain electrodes, which is an inner-located electrode, has an outer circumference which is in the shape of a circle or in the shape of a polygon and that the other of the source and drain electrodes, which is an outer-located electrode, has an inner circumference facing the outer circumference of the inner-located electrode, the inner circumference being of a shape which is substantially concentric with the outer circumference of the inner-located electrode;
forming the organic semiconductor layer, after forming the source electrode and the drain electrode, so as to connect the source electrode and the drain electrode to each other by a process of dropping an organic semiconductor material;
forming a water repellent layer on the source electrode and the drain electrode formed by the electrode forming process;
forming a protection layer on the substrate with the organic semiconductor layer;
removing the water repellent layer; and
forming a contact hole which pierces through the protection layer.
15. A method according to claim 14 , wherein the dropping process in the organic semiconductor layer forming process is an ink jet process.
16. A method according to claim 14 , wherein one drop is applied in the dropping process.
17. A method according to claim 14 , wherein the inner circumference of the outer-located electrode is of a same shape as that of the outer circumference of the inner-located electrode.
18. The method of claim 14 , wherein the inner-located electrode is positioned nearer to a surface of the substrate than the outer-located electrode as measured along a direction perpendicular to the surface.
19. The method of claim 18 , wherein the outer-located electrode overlaps the inner-located electrode and the surface.
20. The method of claim 19 , wherein the inner-located electrode overlaps the surface.
21. The method of claim 14 , wherein the process of dropping results in the organic semiconductor layer having an even thickness.
22. The method of claim 21 , wherein the process of dropping comprises having a drop of the organic semiconductor material land onto a center of the inner-located electrode and then spread radially to reach the outer-located electrode.
23. The method of claim 22 , wherein the process of dropping results in the organic semiconductor layer being aligned from an outer rim of the outer-located electrode to the center of the inner-located electrode and along a direction of alignment that matches a direction of a channel width of the organic thin film transistor.
24. The method of claim 21 , wherein the process of dropping results in the organic semiconductor layer being aligned along a direction of alignment that matches a direction of a channel width of the organic thin film transistor.
25. The method of claim 14 , wherein the process of dropping results in the organic semiconductor layer being aligned along a direction of alignment that matches a direction of a channel width of the organic thin film transistor.
26. The method of claim 14 , wherein the process of dropping results in the organic semiconductor layer being aligned from an outer rim of the outer-located electrode to the center of the inner-located electrode and along a direction of alignment that matches a direction of a channel width of the organic thin film transistor.