SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME

• US 20100123130A1
• Filed: 11/16/2009
• Published: 05/20/2010
• Est. Priority Date: 11/20/2008
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: TAKAHASHI, Masahiro, MIYANAGA, Akiharu, HIROHASHI, Takuya, AKIMOTO, Kengo, SAKATA, Junichiro, KISHIDA, Hideyuki
• Granted Patent: US 8,329,506 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/28079 the final conductor layer next to the insulator being a single metal, e.g. Ta, W, Mo, Al
• CPC Class Codes: H01L 21/28158 Making the insulator
• CPC Class Codes: H01L 29/04 characterised by their crystalline structure, e.g. polycrystalline, cubic or particular orientation of crystalline planes characterised by physical imperfections H01L29/30
• CPC Class Codes: H01L 29/66742 Thin film unipolar transistors
• CPC Class Codes: H01L 29/66969 of devices having semiconductor bodies not comprising group 14 or group 13/15 materials comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials, comprising cuprous oxide or cuprous iodide H01L21/02365
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H01L 29/78693 the semiconducting oxide being amorphous

Abstract

It is an object to provide an oxide semiconductor which is suitable for use in a semiconductor device. Alternatively, it is another object to provide a semiconductor device using the oxide semiconductor. Provided is a semiconductor device including an In—Ga—Zn—O based oxide semiconductor layer in a channel formation region of a transistor. In the semiconductor device, the In—Ga—Zn—O based oxide semiconductor layer has a structure in which crystal grains represented by InGaO₃(ZnO)_m (m=1) are included in an amorphous structure represented by InGaO₃(ZnO)_m (m>0).

Claims

1. A semiconductor device comprising:

a transistor including a channel formation region,

wherein the channel formation region includes an In—

Ga—

Zn—

O based oxide semiconductor layer, and

wherein the In—

Ga—

Zn—

O based oxide semiconductor layer has a structure in which crystal grains represented by InGaZnO₄ are included in an amorphous structure including In, Ga, Zn and O.

2. The semiconductor device according to claim 1, wherein the oxide semiconductor layer is formed by a sputtering method using a target in which a Zn content by atomic percent is less than or equal to an In content by atomic percent and the Zn content by atomic percent is less than or equal to a Ga content by atomic percent.

3. The semiconductor device according to claim 1, wherein a proportion of the crystal grains of the InGaZnO₄ in a whole crystal grains is 80 percents by volume or more.

4. A semiconductor device comprising:

a transistor including a channel formation region,

wherein the channel formation region includes an In—

Ga—

Zn—

O based oxide semiconductor layer,

wherein the In—

Ga—

Zn—

O based oxide semiconductor layer has a structure in which crystal grains represented by InGaZnO₄ are included in an amorphous structure including In, Ga, Zn and O,

wherein a Zn content by atomic percent is less than an In content by atomic percent in the In—

Ga—

Zn—

O based oxide semiconductor layer, and

wherein the Zn content by atomic percent is less than a Ga content by atomic percent in the In—

Ga—

Zn—

O based oxide semiconductor layer.

5. The semiconductor device according to claim 4,

wherein the oxide semiconductor layer is formed by a sputtering method using a target in which a Zn content by atomic percent is less than or equal to an In content by atomic percent and the Zn content by atomic percent is less than or equal to a Ga content by atomic percent.

6. The semiconductor device according to claim 4, wherein a proportion of the crystal grains of the InGaZnO₄ in a whole crystal grains is 80 percents by volume or more.

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

forming an In—

Ga—

Zn—

O based oxide semiconductor layer having an amorphous structure over a substrate by a sputtering method;

heating the In—

Ga—

Zn—

O based oxide semiconductor layer to form an oxide semiconductor layer including crystal grains represented by InGaZnO₄ in the amorphous structure; and

forming a channel formation region of a transistor using the oxide semiconductor layer including the crystal grains represented by InGaZnO₄.

8. The method for manufacturing the semiconductor device according to claim 7, wherein the In—

Ga—

Zn—

O based oxide semiconductor layer having the amorphous structure is formed using a target in which a Zn content by atomic percent is less than or equal to an In content by atomic percent and the Zn content by atomic percent is less than or equal to a Ga content by atomic percent.

9. The method for manufacturing the semiconductor device according to claim 7, wherein a proportion of the crystal grains of the InGaZnO₄ in a whole crystal grains is 80 percents by volume or more.

10. The method for manufacturing a semiconductor device according to claim 7, wherein the heating is performed at 350 degrees centigrade or more.

11. The method for manufacturing a semiconductor device according to claim 7, wherein the heating is performed within a temperature from 350 to 800 degrees centigrade.

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

forming an In—

Ga—

Zn—

O based oxide semiconductor layer having an amorphous structure over a substrate by a sputtering method;

heating the oxide semiconductor layer to form an oxide semiconductor layer including crystal grains represented by InGaZnO₄ in the amorphous structure; and

forming a channel formation region of a transistor using the oxide semiconductor layer including the crystal grains represented by InGaZnO₄,

wherein a Zn content by atomic percent is less than an In content by atomic percent in the In—

Ga—

Zn—

O based oxide semiconductor layer, and

wherein the Zn content by atomic percent is less than a Ga content by atomic percent in the In—

Ga—

Zn—

O based oxide semiconductor layer.

13. The method for manufacturing the semiconductor device according to claim 12, wherein the In—

Ga—

Zn—

O based oxide semiconductor layer having the amorphous structure is formed using a target in which a Zn content by atomic percent is less than or equal to an In content by atomic percent and the Zn content by atomic percent is less than or equal to a Ga content by atomic percent.

14. The method for manufacturing the semiconductor device according to claim 12, wherein a proportion of the crystal grains of the InGaZnO₄ in a whole crystal grains is 80 percents by volume or more.

15. The method for manufacturing a semiconductor device according to claim 12, wherein the heating is performed at 350 degrees centigrade or more.

16. The method for manufacturing a semiconductor device according to claim 12, wherein the heating is performed within a temperature from 350 to 800 degrees centigrade.