Method for producing thin film transistor

Patent metadata

Field	Value
Publication number	US-9691906-B2
Application number	US-201415028966-A
Country	US
Kind code	B2
Filing date	Jul 1, 2014
Priority date	Oct 24, 2013
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

A method for producing a thin film transistor including an oxide semiconductor layer includes: depositing an oxide semiconductor film above a substrate by a sputtering method; and forming the oxide semiconductor layer into a predetermined shape by processing the oxide semiconductor film, wherein in the depositing of an oxide semiconductor film, a first oxide semiconductor film is deposited by using a first power density, and a second oxide semiconductor film is then deposited on the first oxide semiconductor film by using a second power density different from the first power density.

First claim

The invention claimed is:

1. A method for producing a thin film transistor including an oxide semiconductor layer, the method comprising:
depositing an oxide semiconductor film above a substrate by a sputtering method; and
forming the oxide semiconductor layer into a predetermined shape by processing the oxide semiconductor film,
wherein, in the depositing of the oxide semiconductor film, a first oxide semiconductor film is deposited by using a first power density, and a second oxide semiconductor film is deposited on the first oxide semiconductor film by using a second power density different from the first power density,
the first oxide semiconductor film has a thickness of 10 nm or more, and
the second oxide semiconductor film has a thickness of 5 nm or less.

2. The method for producing a thin film transistor according to claim 1 ,
wherein the second power density is greater than the first power density.

3. The method for producing a thin film transistor according to claim 2 ,
wherein the second power density is 110% or more of the first power density.

4. The method for producing a thin film transistor according to claim 1 , comprising:
forming a gate electrode above the substrate;
forming a gate insulation film on the gate electrode;
forming the oxide semiconductor film on the gate insulation film in the depositing of the oxide semiconductor film;
forming the oxide semiconductor layer into a predetermined shape by processing the oxide semiconductor film in the forming of the oxide semiconductor layer;
forming an insulation layer on the oxide semiconductor layer so as to expose a portion of the oxide semiconductor layer; and
forming a source electrode and a drain electrode on the insulation layer so as to be connected to the exposed portion of the oxide semiconductor layer.

5. The method for producing a thin film transistor according to claim 1 ,
wherein the oxide semiconductor film includes a transparent amorphous oxide semiconductor.

6. The method for producing a thin film transistor according to claim 5 ,
wherein the transparent amorphous oxide semiconductor is InGaZnO.

7. The method for producing a thin film transistor according to claim 1 ,
wherein the depositing of the oxide semiconductor film includes, in order:
depositing the first oxide semiconductor film using the first power density;
temporarily stopping a plasma discharge;
switching the first power density to the second power density;
restarting the plasma discharge; and
depositing the second oxide semiconductor film using the second power density.

8. The method for producing a thin film transistor according to claim 7 ,
wherein the first oxide semiconductor film and the second oxide semiconductor film are deposited in a same chamber, and the plasma discharge is temporarily stopped without breaking a vacuum in the same chamber.

9. The method for producing a thin film transistor according to claim 1 ,
wherein, in the depositing of the oxide semiconductor film, the first power density is changed gradually to the second power density in an analog manner.

10. The method for producing a thin film transistor according to claim 1 ,
wherein, in the depositing of the oxide semiconductor film, the first power density is switched to the second power density in a digital manner.

11. The method for producing a thin film transistor according to claim 1 , further comprising:
forming an insulating layer above the substrate to cover the oxide semiconductor layer, the insulating layer including a three-layer structure of a silicon oxide film, an aluminum oxide film, and a silicon oxide film.

Assignees

• Joled Inc

Inventors

• Takeda Eiji
• Kawashima Takahiro

Classifications

• H10P14/3434

  being oxide semiconductor materials (Group IIB-VIA semiconductor materials H10P14/3424) · CPC title

• H10P14/3426

  Oxides · CPC title

• H10P14/3234

  being oxide semiconducting materials (Group IIB-VIA semiconductors H10P14/3224) · CPC title

• H10P14/3226

  Oxides · CPC title

• H10P14/24

  using chemical vapour deposition [CVD] · CPC title