Oxide semiconductor thin film transistors and fabrication methods thereof

• US 7,943,985 B2
• Filed: 07/25/2008
• Issued: 05/17/2011
• Est. Priority Date: 11/30/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Son, Kyung-seok, Ryu, Myung-kwan, Lee, Sang-yoon, Jung, Ji-sim, Kim, Tae-sang, Park, Kyung-bae, Kwon, Jang-yeon
• Primary Examiner(s): Pert; Evan
• Assistant Examiner(s): WILSON, SCOTT R
• Application Number:
  US12/219,661
• Publication Number:
  US 20090140243A1
• Time in Patent Office: 1,026 Days
• Field of Search: 324/248, 257/E29.277, 257/E29.117, 257/E29.273, 257/213, 257/288, 257/327, 257/347, 257/404, 438/197, 438/149, 438/479, 438/517, 438/217
• US Class Current: 257/327
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02614 Transformation of metal, e.g. oxidation, nitridation
• CPC Class Codes: H01L 21/02631 Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• 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

Oxide semiconductor thin film transistors (TFT) and methods of manufacturing the same are provided. The methods include forming a channel layer on a substrate, forming source and drain electrodes at opposing sides of the channel layer, and oxidizing a surface of the channel layer by placing an oxidizing material in contact with the surface of the channel layer, reducing carriers on the surface of the channel layer. Due to the oxidizing agent treatment of the surface of the channel layer, excessive carriers that are generated naturally, or during the manufacturing process, may be more effectively controlled.

Claims

1. A method of manufacturing an oxide semiconductor thin film transistor, the method comprising:

forming an oxide semiconductor channel layer on a substrate;

forming source and drain electrodes at opposing sides of the channel layer; and

oxidizing a surface of the channel layer by placing an oxidizing material in contact with the surface of the channel layer so that carriers on the surface of the channel layer decrease.

2. The method of claim 1, wherein placing the oxidizing material includes forming a liquid oxidizing agent or a self-assembled monolayer (SAM) on the surface of the channel layer.

3. The method of claim 2, wherein forming the source and drain electrodes includes forming a conductive material layer on the substrate;

and patterning the conductive material layer using a wet etching process.

4. The method of claim 2, wherein the source and drain electrodes are formed after forming the channel layer such that the source and drain electrodes contact an upper portion of the opposing sides of the channel layer.

5. The method of claim 4, wherein forming the source and drain electrodes includes forming a conductive material layer on the substrate;

and patterning the conductive material layer using a wet etching process.

6. The method of claim 1, wherein oxidizing the surface of the channel layer includes using an organic insulating material for manufacturing an organic passivation layer, the organic insulating material having a functional group capable of oxidizing the channel layer.

7. The method of claim 6, wherein forming the source and drain electrodes includes forming a conductive material layer on the substrate;

and patterning the conductive material layer using a wet etching process.

8. The method of claim 6, wherein the source and drain electrodes are formed after forming the channel layer such that the source and drain electrodes contact an upper portion of the opposing sides of the channel layer.

9. The method of claim 8, wherein forming the source and drain electrodes includes forming a conductive material layer on the substrate;

and patterning the conductive material layer using a wet etching process.

10. The method of claim 1, wherein the source and drain electrodes are formed prior to forming the channel layer such that the source and drain electrodes contact a lower portion of the opposing sides of the channel layer.

11. The method of claim 10, wherein forming the source and drain electrodes includes forming a conductive material layer on the substrate;

and patterning the conductive material layer using a wet etching process.

12. The method of claim 1, wherein the source and drain electrodes are formed after forming the channel layer such that the source and drain electrodes contact an upper portion of the opposing sides of the channel layer.

13. The method of claim 12, wherein forming the source and drain electrodes includes forming a conductive material layer on the substrate;

and patterning the conductive material layer using a wet etching process.

14. The method of claim 1, wherein forming the source and drain electrodes includes forming a conductive material layer on the substrate;

and patterning the conductive material layer using a wet etching process.

15. The method of claim 1, wherein the oxidizing material is at least one material selected from the group consisting of [MnO₄]-permanganate, [ClO₄]-perchlorate, peroxide compounds and combinations thereof.

16. An oxide semiconductor thin film transistor, comprising:

an oxide semiconductor channel layer on a substrate, a surface of the channel layer being oxidized by an oxidizing material that contacts the surface of the channel layer so that carriers on the surface of the channel layer decrease; and

source and drain electrodes at opposing sides of the channel layer.

17. The oxide semiconductor thin film transistor of claim 16, wherein the oxidizing material includes a liquid oxidizing agent or a self-assembled monolayer (SAM) on the surface of the channel layer.

18. The oxide semiconductor thin film transistor of claim 16, wherein the source and drain electrodes contact a lower portion of the opposing sides of the channel layer.

19. The oxide semiconductor thin film transistor of claim 16, wherein the source and drain electrodes contact an upper portion of the opposing sides of the channel layer.

20. The oxide semiconductor thin film transistor of claim 16, wherein the oxidizing material is at least one material selected from the group consisting of [MnO₄]-permanganate, [ClO₄]-perchlorate, peroxide compounds and combinations thereof.