Organic field effect transistor with a photostructured gate dielectric, method for the production and use thereof in organic electronics

• US 20040219460A1
• Filed: 08/11/2003
• Published: 11/04/2004
• Est. Priority Date: 02/09/2001
• Status: Active Grant

• Current Assignee: PolyIC GmbH & Co. KG (Leonhard KURZ Stiftung & Company KG)
• Original Assignee: PolyIC GmbH & Co. KG (Leonhard KURZ Stiftung & Company KG)
• Inventors: Rost, Henning, Bernds, Adolf, Fix, Walter
• Granted Patent: US 7,238,961 B2
• Time in Patent Office: Days
• US Class Current: 430/311
• CPC Class Codes: H10K 10/464 Lateral top-gate IGFETs comprising only a single gate
• CPC Class Codes: H10K 10/468 characterised by the gate dielectrics
• CPC Class Codes: H10K 19/00 Integrated devices, or assemblies of multiple devices, comprising at least one organic element specially adapted for rectifying, amplifying, oscillating or switching, covered by group H10K10/00
• CPC Class Codes: H10K 19/80 Interconnections, e.g. terminals
• CPC Class Codes: H10K 71/211 by selective transformation of an existing layer
• CPC Class Codes: H10K 71/60 Forming conductive regions or layers, e.g. electrodes
• CPC Class Codes: H10K 77/111 Flexible substrates
• CPC Class Codes: H10K 85/111 comprising aromatic, heteroaromatic, or aryl chains, e.g. polyaniline, polyphenylene or polyphenylene vinylene
• CPC Class Codes: H10K 85/1135 Polyethylene dioxythiophene [PEDOT]; Derivatives thereof

Abstract

The invention relates to an organic field effect transistor which is especially characterized by a cross-linked, structured insulating layer (4) on which the gate electrode (5) is arranged. The structure of the OFET ensures that the gate electrode (5) of an OFET can be used as a strip conductor to the source electrode (2) of the next transistor and can be used in the construction of larger circuits.

Claims

1. Organic field effect transistor, characterized in that there are disposed on a flexible substrate (1), in a first layer, source and drain electrodes (2, 2′

) as well as a semiconductor (3) on which, in a second layer, an insulator (4) is pattern-formed and on which, in a third layer, a gate electrode (5) is deposited.

2. Organic field effect transistor according to claim 1, characterized in that the substrate is ultrathin glass (glass foil) or a plastic foil.

3. Organic field effect transistor according to claim 2, characterized in that the substrate (1) is polyethylene terephthalate or in particular polyimide foil.

4. Organic field effect transistor according to claim 1, characterized in that the source and drain electrodes (2, 2′

) are formed from indium tin oxide (ITO), polyaniline (PANI) and/or conductive polymers.

5. Organic field effect transistor according to claim 1, characterized in that the semiconductor (3) is formed from conjugated polymers or oligomers.

6. Organic field effect transistor according to claim 1, characterized in that the insulator (4) is formed from an insulator material crosslinked with a crosslinker in the presence of a photoinitiator.

7. Organic field effect transistor according to claim 6, characterized in that the insulator material is selected from poly(4-hydroxystyrene) or from melamine-formaldehyde resins containing hydroxyl groups.

8. Organic field effect transistor according to claim 6, characterized in that the crosslinker is acid-sensitive, specifically hexamethoxymethylmelamine (HMMM).

9. Organic field effect transistor according to claim 6, characterized in that the photoinitiator is selected from diphenyliodonium tetrafluoroborate and triphenylsulfonium hexafluoroantimonate.

10. Organic field effect transistor according to claim 1, characterized in that the gate electrode is formed from polyaniline, other conductive polymers or carbon black.

16. Method according to claim 1, characterized in that UV light is used for exposure.

17. Method according to claim 1, characterized in that baking is performed at a temperature between 100°

C. and 140°

C.

18. Method according to claim 17, characterized in that baking is performed at a temperature of 120°

C.

19. Use of the organic field effect transistor according to claim 1 in organic electronics.

20. Use of the organic field effect transistor according to claim 1 for identification stickers (ID tags), electronic watermarks, electronic barcodes, electronic toys, electronic tickets, in product or piracy protection or anti-theft security.

11. Method for producing an organic field effect transistor wherein a flexible substrate (1) is provided with a source and drain electrode (2, 2′

) as well as a semiconductor (3) in the usual manner, characterized in that an insulator (4) is deposited on the semiconductor (3) by applying an insulator material solution containing an acid-sensitive crosslinker as well as a photoinitiator, exposing it through a shadow mask covering the source and drain electrodes (2, 2′

), and then baking it, crosslinking being effected at the exposed areas and the gate electrode (5) being deposited on the thus crosslinked and patterned insulator (4).

12. Method according to claim 11, characterized in that the insulator material is selected from poly(4-hydroxystyrene) or melamine-formaldehyde resins containing hydroxyl groups.

13. Method according to claim 11, characterized in that the crosslinker is acid-sensitive, specifically hexamethoxymethylmelamine (HMMM).

14. Method according to claim 13, characterized in that the photoinitiator produces an acid under the effect of light and is selected specifically from diphenyliodonium tetrafluoroborate and triphenylsulfonium hexafluoroantimonate.

15. Method according to claim 11, characterized in that the solution containing the insulator material, the crosslinker and the photoinitiator is applied by spin-coating or silk-screen printing.