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

• US 7,238,961 B2
• Filed: 01/29/2002
• Issued: 07/03/2007
• Est. Priority Date: 02/09/2001
• Status: Expired due to Fees

• 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
• Primary Examiner(s): Hu; Shouxiang
• Application Number:
  US10/467,636
• Publication Number:
  US 20040219460A1
• Time in Patent Office: 1,981 Days
• Field of Search: 257/40, 257/410, 257/411, 438/82, 438/99, 438/780
• US Class Current: 257/40
• 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, comprising:

a flexible substrate;

a first layer on the substrate;

source and drain electrodes and a semiconductor in the first layer;

an insulator forming a second layer on the first layer, the insulator being pattern-formed and formed from an insulator material crosslinked with a crosslinker in the presence of a photoinitiator, the insulator pattern being produced by crosslinking the insulator in the desired pattern by photolithography with uncrosslinked insulator outside the pattern and then removing the uncrosslinked insulator material; and

a gate electrode on the second layer forming a third layer.

2. Organic field effect transistor according to claim 1, wherein the substrate is an ultrathin glass foil or a plastic foil.

3. Organic field effect transistor according to claim 2, wherein the substrate is polyethylene terephthalate or a polyimide foil.

4. Organic field effect transistor according to claim 1, wherein the source and drain electrodes are formed from indium tin oxide (ITO), polyaniline (PANI) and/or conductive polymers.

5. Organic field effect transistor according to one of claim 1,

wherein the semiconductor is formed from conjugated polymers or oligomers.

6. Organic field effect transistor according to claim 1, wherein the insulator material is selected from poly(4-hydroxystyrene) or from melamine-formaldehyde resins containing hydroxyl groups.

7. Organic field effect transistor according to claim 1, wherein the crosslinker is acid-sensitive, including hexamethoxymethylmelamine (HMMM).

8. Organic field effect transistor according to claim 1, wherein the photoinitiator is selected from diphenyliodonium tetrafluoroborate and triphenylsulfonium hexafluoroantimonate.

9. Organic field effect transistor according to claim 1, wherein the gate electrode is formed from polyaniline, other conductive polymers or carbon black.

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

11. 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.

12. Organic field effect transistor according to claim 1, wherein the insulator pattern is produced by patterning the insulator with photolithography without using a photoresist.

13. Method far producing an organic field effect transistor comprising:

providing a flexible substrate with a source and drain electrode and a semiconductor;

forming an insulator from an insulator material crosslinked with a crosslinker in the presence of a photoinitiator by applying an insulator material solution containing an acid-sensitive crosslinker and a photoinitiator to the semiconductor;

exposing the insulator through a shadow mask covering the source and drain electrodes;

patterning the insulator pattern by crosslinking the insulator in the desired pattern by photolithography with uncrosslinked insulator outside the pattern and then removing the uncrosslinked insulator material including baking to effect the crosslinking and patterning of the insulator at the exposed areas; and

depositing a gate electrode on the thus crosslinked and patterned insulator.

14. Method according to claim 13, wherein the insulator material is selected from poly(4-hydroxystyrene) or melamine-formaldehyde resins containing hydroxyl groups.

15. Method according to claim 13, wherein the crosslinker is acid-sensitive, including hexamethoxymethylmelamine (HMMM).

16. Method according to claim 15, wherein the photoinitiator produces an acid under the effect of light and is selected specifically from diphenyliodonium tetrafluoroborate and triphenylsulfonium hexafluoroantimonate.

17. Method according to claim 13, wherein the solution containing the insulator material, the crosslinker and the photoinitiator is applied by spin-coating or silk screen printing.

18. Method according to claim 13, wherein UV light used for exposure.

19. Method according to claim 13, wherein baking is performed at a temperature between 100°

C. and 140°

C.

20. Method according to claim 19, wherein baking is performed at a temperature of 12°

C.