METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

• US 20120295397A1
• Filed: 05/09/2012
• Published: 11/22/2012
• Est. Priority Date: 05/19/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: KOEZUKA, Junichi, SATO, Yuhei, YAMAZAKI, Shunpei
• Granted Patent: US 9,117,920 B2
• Time in Patent Office: Days
• US Class Current: 438/104
• CPC Class Codes: H01L 29/78693 the semiconducting oxide being amorphous

Abstract

Stable electrical characteristics and high reliability are provided to a semiconductor device including an oxide semiconductor. In a process of manufacturing a transistor including an oxide semiconductor film, an amorphous oxide semiconductor film is formed, and oxygen is added to the amorphous oxide semiconductor film, so that an amorphous oxide semiconductor film containing excess oxygen is formed. Then, an aluminum oxide film is formed over the amorphous oxide semiconductor film, and heat treatment is performed thereon to crystallize at least part of the amorphous oxide semiconductor film, so that a crystalline oxide semiconductor film is formed.

Claims

1. A method for manufacturing a semiconductor device, comprising the steps of:

forming an insulating film, an aluminum oxide film, and an amorphous oxide semiconductor film between the insulating film and the aluminum oxide film; and

performing heat treatment on the amorphous oxide semiconductor film to form an oxide semiconductor film including a crystal,

wherein the amorphous oxide semiconductor film has a region containing oxygen in excess of a stoichiometric ratio in the oxide semiconductor in a crystalline state as a result of adding oxygen thereto.

4. The method for manufacturing a semiconductor device according to any one of claims 1 to 3, wherein the crystal included in the oxide semiconductor film has a c-axis substantially perpendicular to a surface.

5. The method for manufacturing a semiconductor device according to any one of claims 1 to 3, further comprising the step of forming a gate insulating film over the amorphous oxide semiconductor film,

wherein the oxygen is added to the amorphous oxide semiconductor film through the gate insulating film.

6. The method for manufacturing a semiconductor device according to any one of claims 1 to 3, further comprising the steps of:

forming a gate insulating film over the amorphous oxide semiconductor film; and

forming a gate electrode layer over the gate insulating film,

wherein the oxygen is added to the amorphous oxide semiconductor film through the gate insulating film.

7. The method for manufacturing a semiconductor device according to any one of claims 1 to 3, further comprising the step of performing heat treatment on the amorphous oxide semiconductor film before adding the oxygen to release hydrogen or moisture from the amorphous oxide semiconductor film.

8. The method for manufacturing a semiconductor device according to any one of claims 1 to 3, wherein the oxygen is added to the amorphous oxide semiconductor film using an ion implantation method.

9. The method for manufacturing a semiconductor device according to any one of claims 1 to 3, further comprising the step of forming an oxide insulating film between the amorphous oxide semiconductor film and the aluminum oxide film.

2. A method for manufacturing a semiconductor device, comprising the steps of:

forming an insulating film;

forming an amorphous oxide semiconductor film over the insulating film;

adding oxygen to the amorphous oxide semiconductor film;

forming an aluminum oxide film over the amorphous oxide semiconductor film containing added oxygen; and

performing heat treatment on the amorphous oxide semiconductor film containing added oxygen to form an oxide semiconductor film including a crystal,

wherein the amorphous oxide semiconductor film has a region containing oxygen in excess of a stoichiometric ratio in the oxide semiconductor in a crystalline state.

3. A method for manufacturing a semiconductor device, comprising the steps of:

forming an insulating film;

forming an amorphous oxide semiconductor film over the insulating film;

forming an aluminum oxide film over the amorphous oxide semiconductor film;

adding oxygen to the amorphous oxide semiconductor film through the aluminum oxide film; and

performing heat treatment on the amorphous oxide semiconductor film containing added oxygen to form an oxide semiconductor film including a crystal,

wherein the amorphous oxide semiconductor film has a region containing oxygen in excess of a stoichiometric ratio in the oxide semiconductor in a crystalline state.