Organic thin-film transistor

• US 20050194640A1
• Filed: 10/18/2004
• Published: 09/08/2005
• Est. Priority Date: 10/17/2003
• Status: Abandoned Application

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Insolvency Services Group, Inc.
• Inventors: Lazarev, Pavel I.
• Application Number:
  US10/968,404
• Publication Number:
  US 20050194640A1
• Time in Patent Office: Days
• US Class Current: 257/347
• CPC Class Codes: H10K 10/46 Field-effect transistors, e.g. organic thin-film transistors [OTFT] H10K10/43 takes precedence
• CPC Class Codes: H10K 10/464 Lateral top-gate IGFETs comprising only a single gate
• CPC Class Codes: H10K 10/466 Lateral bottom-gate IGFETs comprising only a single gate
• CPC Class Codes: H10K 71/191 characterised by provisions for the orientation or alignment of the layer to be deposited
• CPC Class Codes: H10K 85/731 Liquid crystalline materials

Abstract

The present invention relates to organic thin-film transistors using an organic compound in the semiconductor layer thereof. The organic semiconductor layer is made by means of Cascade Crystallization Process. Said layer is characterized by a globally ordered crystalline structure with intermolecular spacing of 3.4±0.3 Å in the direction of one crystal axis. This layer is formed by rodlike supramolecules comprising at least one polycyclic organic compound with conjugated π-system and has electron-hole type of conductivity.

Claims

1. An organic thin film transistor comprising

an organic semiconductor layer,

an insulator layer with at least a part of one surface in contact with at least a part of one surface of the semiconductor layer,

electrically conducting gate electrode located on the other surface of the insulator layer,

electrically conductive source and drain electrodes in contact with one surface of the organic semiconductor layer,

wherein said organic semiconductor layer is characterized by a globally ordered crystalline structure with intermolecular spacing of 3.4±

0.3 Å

in the direction of one crystal axis, is formed by rodlike supramolecules comprising at least one polycyclic organic compound with conjugated π

-system, and possesses electron-hole type of conductivity.

2. The organic thin film transistor according to claim 1, further comprising a substrate which carries said organic semiconductor layer and insulator layer.

3. The organic thin film transistor according to claim 2, wherein said electrically conducting gate electrode is located on the substrate;

the insulator layer is located on said electrically conducting gate electrode and is in contact with said gate electrode;

the organic semiconductor layer is located on said insulator layer substantially overlapping with said gate electrode; and

the electrically conductive source and drain electrodes are located on said organic semiconductor layer and are in contact with said layer.

4. The organic thin film transistor according to claim 2, wherein the electrically conductive source and drain electrodes are located on the substrate;

the organic semiconductor layer is located on said source electrode, drain electrode and the substrate and is in contact with said source electrode, drain electrode and the substrate;

the insulator layer is located on said organic semiconductor layer and is in contact with said layer; and

said electrically conducting gate electrode is located on said insulator layer and is in contact with said insulator layer.

5. The organic thin film transistor according to claim 2, wherein said electrically conducting gate electrode is located on the substrate;

the insulator layer is located on said electrically conducting gate electrode and is in contact with said gate electrode;

the electrically conductive source and drain electrodes are located on said insulator layer and are in contact with said insulator layer; and

the organic semiconductor layer is located on and in contact with said source electrode, drain electrode and the insulator layer.

6. The organic thin film transistor according to claim 2, wherein the organic semiconductor layer is located on the substrate;

the electrically conductive source and drain electrodes are located on said organic semiconductor layer and are in contact with said organic semiconductor layer;

the insulator layer is located on said source electrode, drain electrode and organic semiconductor layer and is in contact with said source and drain electrodes and said semiconductor layer; and

the electrically conducting gate electrode is located on said insulator layer and is in contact with said insulator layer.

7. The organic thin film transistor according to claim 1, wherein electrically conductive source and drain electrodes are aligned with respect to said gate electrode.

8. The organic thin film transistor according to claim 1, further comprising an insulator passivation layer located on top of said transistor to protect the transistor from further processing exposures and from the ambient factors.

9. The organic thin film transistor according to claim 2, wherein the substrate is selected from the group comprising glass, plastic, quartz, and undoped silicon.

10. The organic thin film transistor according to claim 9, wherein said plastic substrate is selected from the group comprising polycarbonate, Mylar, and polyimide.

11. The organic thin film transistor according to claim 1, wherein the organic semiconductor layer is made of an organic semiconductor of n-type.

12. The organic thin film transistor according to claim 11, wherein the gate electrode is made of a material with a high electron work function.

13. The organic thin film transistor according to claim 12, wherein material of said gate electrode is selected from the group comprising nickel, gold, platinum, lead, ITO, and combinations thereof.

14. The organic thin film transistor according to claim 11, wherein the source and drain electrodes are made of a material with a low electron work function.

15. The organic thin film transistor according to claim 14, wherein material of said gate electrode is selected from the group comprising chromium, titanium, copper, aluminum, molybdenum, tungsten, indium, silver, calcium, and combinations thereof.

16. The organic thin film transistor according to claim 1, wherein the organic semiconductor layer is made of an organic semiconductor of p-type.

17. The organic thin film transistor according to claim 16, wherein the source and drain electrodes are made of a material with a low electron work function.

18. The organic thin film transistor according to claim 17, wherein material of said source and drain electrodes is selected from the group comprising chromium, titanium, copper, aluminum, molybdenum, tungsten, indium, silver, calcium, and combinations thereof.

19. The organic thin film transistor according to claim 18, wherein the gate electrode is made of a material with a high electron work function.

20. The organic thin film transistor according to claim 19, wherein material of said gate electrode is selected from the group comprising nickel, gold, platinum, lead, ITO, and combinations thereof.

21. The organic thin film transistor according to claim 1, wherein said gate electrode has a thickness in the range between 30 nm and 500 nm, and said electrode is produced by a process selected from the group comprising evaporation, sputtering, chemical vapor deposition, electrodeposition, spin coating, and electroless plating.

22. The organic thin film transistor according to claim 1, wherein material of said insulator layer is selected from the group comprising silicon dioxide, silicon oxide, barium strontium titanate, barium zirconate titanate, lead zirconate titanate, lead lanthanum titanate, barium titanate, strontium titanate, barium magnesium fluoride, tantalum pentoxide, titanium dioxide and yttrium trioxide.

23. The organic thin film transistor according to claim 1, wherein said insulator layer has a thickness in the range between 80 nm and 1000 nm.

24. The organic thin film transistor according to claim 1, wherein said insulator layer is produced by a process selected from the group comprising sputtering, chemical vapor deposition, sol gel coating, evaporation and laser ablation deposition.

25. The organic thin film transistor according to claim 1, wherein at least one electrically conducting gate electrode is a multilayer structure comprising layers made of different conducting materials.

26. The organic thin film transistor according to claim 1, wherein at least one electrically conducting source electrode is the multilayer structure comprising layers made of different conducting materials.

27. The organic thin film transistor according to claim 1, wherein at least one electrically conducting drain electrode is the multilayer structure comprising layers made of different conducting materials.