Method of making a field effect transistor

• US 6,060,338 A
• Filed: 01/12/1999
• Issued: 05/09/2000
• Est. Priority Date: 01/10/1989
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation), Mitsubishi Electric Corporation, Sumitomo Chemical Company Limited
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation), Sumitomo Chemical Company Limited
• Inventors: Tanaka, Toshihiko, Fuchigami, Hiroyuki, Tsumura, Akira, Koezuka, Hiroshi, Doi, Syuji
• Primary Examiner(s): Bowers, Charles
• Assistant Examiner(s): CHRISTIANSON, KEITH ALAN
• Application Number:
  US09/228,936
• Time in Patent Office: 483 Days
• Field of Search: 438/22, 438/30, 438/99, 438/149, 438/151, 257/40, 257/72
• US Class Current: 438/99
• CPC Class Codes: G02F 1/133302 Rigid substrates, e.g. inorganic substrates
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• 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 10/484 characterised by the channel regions
• CPC Class Codes: H10K 19/10 comprising field-effect transistors
• CPC Class Codes: H10K 71/211 by selective transformation of an existing layer
• CPC Class Codes: H10K 71/30 Doping active layers, e.g. electron transporting layers
• CPC Class Codes: H10K 85/111 comprising aromatic, heteroaromatic, or aryl chains, e.g. polyaniline, polyphenylene or polyphenylene vinylene
• CPC Class Codes: H10K 85/113 Heteroaromatic compounds comprising sulfur or selene, e.g. polythiophene
• CPC Class Codes: H10K 85/114 Poly-phenylenevinylene; Derivatives thereof

Abstract

A method of fabricating a field effect transistor including forming a gate electrode on an electrically insulating substrate; forming an electrically insulating film on the substrate covering the gate electrode; forming source and drain electrodes on the electrically insulating film on opposite sides of the gate electrode; forming a semiconducting film of a π-conjugated polymer on the source and drain electrodes and on the electrically insulating film between the source and drain electrodes.

Claims

1. A method of fabricating a field effect transistor comprising:

forming a gate electrode on an electrically insulating substrate;

forming an electrically insulating film on the substrate covering the gate electrode;

forming source and drain electrodes on the electrically insulating film on opposite sides of the gate electrode; and

forming a semiconducting film of a π

-conjugated polymer having the chemical structure ##STR16## (where R₁ and R₂ are one of hydrogen, an alkyl group, and an alkoxyl group, and n is an integer equal to at least

     10), covering the source and drain electrodes and on the electrically insulating film between the source and drain electrodes.

2. The method of claim 1 including forming the film of a first π

-conjugated polymer by heating a film of a precursor of the first π

-conjugated polymer, the precursor of the first π

-conjugated polymer having the chemical structure ##STR17## (where R₃ is a hydrocarbon group having 1 to 10 carbon atoms and n is an integer equal to at least

     10).

3. The method of claim 2 wherein R₃ is CH₃ and the first π

-conjugated polymer is poly(2,5-thienylene vinylene).

7. The method of claim 2 wherein the precursor of the π

-conjugated polymer includes an alkoxy group, the method including heating the precursor in an ambient including an inert gas.

8. The method of claim 7 including heating the precursor of the π

-conjugated polymer to a temperature in a range of from 200 to 300°

C. to produce the semiconductor film.

9. The method of claim 7 wherein the ambient includes a protonic acid vapor.

13. The method of claim 1 wherein the source and drain electrodes are spaced apart by an opening and the gate electrode is disposed on the electrically insulating substrate opposite the opening between the source and drain electrodes.

4. A method of fabricating a field effect transistor comprising:

forming a gate electrode on an electrically insulating substrate;

forming an electrically insulating film on the substrate and covering the gate electrode;

forming a semiconducting film of a π

-conjugated polymer having the chemical structure ##STR18## (where R₁ and R₂ are one of hydrogen, an alkyl group, and an alkoxyl group, and n is an integer equal to at least

     10), on the electrically insulating film; and

forming source and drain electrodes on the semiconducting film on opposite sides of the gate electrode.

5. The method of claim 4 including forming the film of a π

-conjugated polymer by heating a film of a precursor of the π

-conjugated polymer, the precursor of the π

-conjugated polymer having the chemical structure ##STR19## (where R₃ is a hydrocarbon group having 1 to 10 carbon atoms and n is an integer equal to at least

     10).

6. The method of claim 5 wherein R₃ is CH₃ and the π

-conjugated polymer is poly(2,5-thienylene vinylene).

10. The method of claim 5 wherein the precursor of the π

-conjugated polymer includes an alkoxy group, the method including heating the precursor in an ambient including an inert gas.

11. The method of claim 10 including heating the precursor of the π

-conjugated polymer to a temperature in a range of from 200 to 300°

C. to produce the semiconductor film.

12. The method of claim 10 wherein the ambient includes a protonic acid vapor.

14. The method of claim 4 wherein the source and drain electrodes are spaced apart by an opening and the gate electrode is disposed on the electrically insulating substrate opposite the opening between the source and drain electrodes.

15. A method of fabricating a field effect transistor comprising:

forming an electrically insulating film covering opposed first and second surfaces of a substrate;

forming source and drain electrodes spaced apart by an opening on the electrically insulating film opposite the first surface of the substrate;

forming a semiconducting film of a π

-conjugated polymer having the chemical structure ##STR20## (where R₁ and R₂ are one of hydrogen, an alkyl group, and an alkoxyl group, and n is an integer equal to at least

     10), covering the source and drain electrodes and the electrically insulating film in the opening between the source and drain electrodes;

removing a part of the electrically insulating film opposite the second surface of the substrate, opposite the opening between the source and drain electrodes, exposing the substrate; and

forming a gate electrode on the second surface of the substrate opposite the opening between the source and drain electrodes.

16. The method of claim 15 including forming the film of a first π

-conjugated polymer by heating a film of a precursor of the first π

-conjugated polymer, the precursor of the first π

-conjugated polymer having the chemical structure ##STR21## (where R₃ is a hydrocarbon group having 1 to 10 carbon atoms and n is an integer equal to at least

     10).

17. The method of claim 16 wherein R₃ is CH₃ and the first π

-conjugated polymer is poly(2,5-thienylene vinylene).

18. The method of claim 16 wherein the precursor of the π

-conjugated polymer includes an alkoxy group, the method including heating the precursor in an ambient including an inert gas.

19. The method of claim 18 including heating the precursor of the π

-conjugated polymer to a temperature in a range of from 200 to 300°

C. to produce the semiconductor film.

20. The method of claim 18 wherein the ambient includes a protonic acid vapor.