THIN FILM TRANSISTOR, METHOD OF MANUFACTURING THE SAME, AND DISPLAY DEVICE

• US 20100224871A1
• Filed: 02/22/2010
• Published: 09/09/2010
• Est. Priority Date: 03/04/2009
• Status: Active Grant

• Current Assignee: JDI Design and Development GK
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Miyashita, Hiroko, Terai, Yasuhiro, Yamaguchi, Norihiko, Taniguchi, Satoshi
• Granted Patent: US 8,748,878 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• 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

The present application provides a thin film transistor and a method of manufacturing same capable of suppressing diffusion of aluminum to oxide semiconductor and selectively etching oxide semiconductor and aluminum oxide. The thin film transistor includes: a gate electrode; a channel layer whose main component is oxide semiconductor; a gate insulating film provided between the gate electrode and the channel layer; a sealing layer provided on the side opposite to the gate electrode, of the channel layer; and a pair of electrodes which are in contact with the channel layer and serve as a source and a drain. The sealing layer includes at least a first insulating film made of a first insulating material, and a second insulating film made of a second insulting material having etching selectivity to each of the oxide semiconductor and the first insulating material and provided between the first insulating film and the channel layer.

Claims

1. A thin film transistor comprising:

a gate electrode;

a channel layer whose main component is oxide semiconductor;

a gate insulating film provided between the gate electrode and the channel layer;

a sealing layer provided on the side opposite to the gate electrode, of the channel layer; and

a pair of electrodes which are in contact with the channel layer and serve as a source and a drain,

wherein the sealing layer includes at least

a first insulating film made of a first insulating material, and

a second insulating film made of a second insulting material having etching selectivity to each of the oxide semiconductor and the first insulating material and provided between the first insulating film and the channel layer.

2. The thin film transistor according to claim 1, wherein the oxide semiconductor is at least one of ZnO, ITO, and In-M-Zn—

O, wherein M is at least one of Ga, Al, Fe, and Sn.

3. The thin film transistor according to claim 2, wherein the first insulating material is Al₂O₃, and the second insulating material is at least one of SiO_X, SiN_X, Y₂O₃, TaO, and HfO and their oxynitrides.

4. The thin film transistor according to claim 1, wherein the gate electrode, the gate insulating film, the channel layer, and the sealing layer are provided in this order on a substrate.

5. The thin film transistor according to claim 1, wherein the sealing layer, the channel layer, the gate insulating film, and the gate electrode are provided in this order on a substrate.

6. The thin film transistor according to claim 1, wherein thickness of the first insulating film is 10 nm to 500 nm both inclusive.

7. A method of manufacturing a thin film transistor, comprising the steps of:

forming a gate electrode on a substrate;

forming a gate insulating film on the gate electrode and, after that, forming a channel layer whose main component is oxide semiconductor on the gate insulating film;

forming a second insulating film made of a second insulating material and a first insulating film made of a first insulating material in this order on the channel layer;

forming a channel protection film on the first insulating film and, after that, etching the first insulating film using the second insulating film as a stopper;

etching the second insulating film using the processed first insulating film as a mask and using the channel layer as a stopper; and

forming a pair of electrodes serving as a source and a drain so as to be in contact with the channel layer,

wherein the second insulating material has etching selectivity to each of the oxide semiconductor and the first insulating material.

8. The method of manufacturing a thin film transistor according to claim 7, wherein the oxide semiconductor is at least one of ZnO, ITO, and In-M-Zn—

O, wherein M is at least one of Ga, Al, Fe, and Sn.

9. The method of manufacturing a thin film transistor according to claim 8, wherein the first insulating material is Al₂O₃, and the second insulating material is at least one of SiO_X, SiN_X, Y₂O₃, TaO, and HfO and their oxynitrides.

13. The method of manufacturing a thin film transistor according to claim 7, wherein at least the channel layer and the second insulating film are continuously formed in vacuum.

14. The method of manufacturing a thin film transistor according to claim 7, wherein the channel layer, the second insulating film, and the first insulating film are continuously formed in vacuum.

15. The method of manufacturing a thin film transistor according to claim 7, wherein the first insulating film is dry-etched with chlorine-based gas using the second insulating film as a stopper and, after that, the second insulating film is dry-etched with fluorine-based gas using the channel layer as a stopper.

16. The method of manufacturing a thin film transistor according to claim 7, wherein the first insulating film is etched with a phosphoric-acid-based solution using the second insulating film as a stopper and, after that, the second insulating film is dry-etched with fluorine-based gas using the channel layer as a stopper.

10. A method of manufacturing a thin film transistor, comprising the steps of:

forming a first insulating film made of a first insulting material and a second insulting film made of a second insulating material in this order on a substrate;

forming a pair of electrodes serving as a source and a drain on the second insulating film;

forming a channel layer whose main component is oxide semiconductor on the second insulating film and the pair of electrodes;

forming a gate insulating film on the channel layer and etching the channel layer using the pair of electrodes as a stopper; and

forming a gate electrode on the gate insulating film,

wherein the second insulating material has etching selectivity to each of the oxide semiconductor and the first insulating material.

11. The method of manufacturing a thin film transistor according to claim 10, wherein the oxide semiconductor is at least one of ZnO, ITO, and In-M-Zn—

O, wherein M is at least one of Ga, Al, Fe, and Sn.

12. The method of manufacturing a thin film transistor according to claim 11, wherein the first insulating material is Al₂O₃, and the second insulating material is at least one of SiO_X, SiN_X, Y₂O₃, TaO, and HfO and their oxynitrides.

17. A display device comprising a thin film transistor and a display element, wherein the thin film transistor includes:

a gate electrode;

a channel layer whose main component is oxide semiconductor;

a gate insulating film provided between the gate electrode and the channel layer;

a sealing layer provided on the side opposite to the gate electrode, of the channel layer; and

a pair of electrodes which are in contact with the channel layer and serve as a source and a drain, and

the sealing layer includes at least

a first insulating film made of a first insulating material; and

a second insulating film made of a second insulting material having etching selectivity to each of the oxide semiconductor and the first insulating material and provided between the first insulating film and the channel layer