SEMICONDUCTOR LAYER FOR THIN FILM TRANSISTORS

• US 20080286907A1
• Filed: 05/16/2007
• Published: 11/20/2008
• Est. Priority Date: 05/16/2007
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Li, Yuning, Ong, Beng S.
• Application Number:
  US11/749,419
• Publication Number:
  US 20080286907A1
• Time in Patent Office: Days
• US Class Current: 438/141
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02628 using solutions
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

A method for making a zinc oxide semiconductor layer for a thin film transistor using solution processing at low temperatures is disclosed. The method comprises making a solution comprising a zinc salt and a complexing agent; applying the solution to a substrate; and heating the solution to form a semiconductor layer on the substrate. A thin film transistor using this zinc oxide semiconductor layer has good mobility and on/off ratio.

Claims

1. A method of making a zinc oxide semiconductor layer for a thin film transistor, comprising:

providing a solution comprising a zinc salt and a complexing agent;

contacting a substrate with the solution; and

heating the solution to form a zinc oxide semiconductor layer on the substrate.

2. The method of claim 1, wherein the zinc salt is selected from the group consisting of zinc nitrate, zinc chloride, zinc bromide, zinc oxalate, zinc acetylacetonate, zinc sulfate, zinc acetate, and their hydrates.

3. The method of claim 1, wherein the complexing agent is a carboxylic acid or an organoamine.

4. The method of claim 1, wherein the complexing agent is an organoamine selected from the group consisting of hexamethylenetetramine, ethanolamine, aminopropanol, diethanolamine, 2-methylaminoethanol, N,N-dimethylaminoethanol, methoxyethylamine, methoxypropylamine, diaminoethane, diaminopropane, diaminobutane, diaminocyclohexane, and mixtures thereof.

5. The method of claim 1, wherein the molar ratio of zinc salt to complexing agent in the solution is from about 0.5 to about 10.

6. The method of claim 1, wherein the concentration of Zn²⁺ in the solution is from about 0.01M to about 5.0M.

7. The method of claim 1, wherein the substrate is contacted with the solution by submerging the substrate therein.

8. The method of claim 1, wherein the substrate is contacted with the solution by depositing the solution thereupon.

9. The method of claim 8, wherein the method of liquid deposition is selected from the group consisting of spin coating, blade coating, rod coating, dip coating, screen printing, microcontact printing, ink jet printing, and stamping.

10. The method of claim 1, wherein the heating is performed by heating to a temperature of from about 50°

C. to about 300°

C.

11. The method of claim 1, wherein the heating is performed by heating to a temperature of from about 50°

C. to about 150°

C.

12. The method of claim 1, wherein the solution is heated for a period of from about 1 minute to about 24 hours.

13. The method of claim 1, wherein the solution is heated for a period of from about 1 minute to about 200 minutes.

14. The method of claim 1, wherein the heating is performed by heating at a rate of from about 0.5°

C. to about 100°

C. per minute.

15. The method of claim 1, wherein the heating is performed by heating at a rate of from about 1°

C. per minute.

16. The method of claim 1, further comprising cleaning and drying the substrate.

17. The method of claim 1, wherein the resulting thin film transistor has a field effect mobility of at least 0.1 cm²/V·

sec.

18. The method of claim 1, wherein the resulting thin film transistor has a field effect mobility of at least 0.5 cm²/V·

sec.

19. The method of claim 1, wherein the resulting semiconductor layer has a current on/off ratio greater than about 10³.

20. The method of claim 1, wherein the substrate comprises a film or sheet of glass, silicon, or polymeric material.

21. The thin film transistor formed by the method of claim 1.