Method for manufacturing a semiconductor device

• US 9,318,617 B2
• Filed: 12/18/2014
• Issued: 04/19/2016
• Est. Priority Date: 09/24/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Sakakura, Masayuki, Watanabe, Ryosuke, Sakata, Junichiro, Akimoto, Kengo, Miyanaga, Akiharu, Hirohashi, Takuya, Kishida, Hideyuki
• Primary Examiner(s): DANG, PHUC T
• Application Number:
  US14/574,964
• Publication Number:
  US 20150104901A1
• Time in Patent Office: 488 Days
• Field of Search: 257/43, 438/396
• US Class Current: 1/1
• CPC Class Codes: H01L 21/2636 for heating, e.g. electron beam heating
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• 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 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/12 characterised by the materials of which they are formed
• CPC Class Codes: H01L 29/24 including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• CPC Class Codes: H01L 29/41733 for thin film transistors with insulated gate
• 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 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621

Abstract

It is an object to provide a highly reliable semiconductor device with good electrical characteristics and a display device including the semiconductor device as a switching element. In a transistor including an oxide semiconductor layer, a needle crystal group provided on at least one surface side of the oxide semiconductor layer grows in a c-axis direction perpendicular to the surface and includes an a-b plane parallel to the surface, and a portion except for the needle crystal group is an amorphous region or a region in which amorphousness and microcrystals are mixed. Accordingly, a highly reliable semiconductor device with good electrical characteristics can be formed.

Claims

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

performing a first heat treatment in a chamber in which a substrate and a target are provided;

forming an oxide semiconductor film over the substrate by sputtering method using the target; and

performing a second heat treatment on the oxide semiconductor film,

wherein the oxide semiconductor film is formed in the chamber without exposure to air after the first heat treatment,

wherein moisture remaining on an inner wall of the chamber and moisture remaining in the target are reduced by the first heat treatment,

wherein gas in the chamber is exhausted during the first heat treatment, and

wherein hydrogen or moisture in the oxide semiconductor film is reduced by the second heat treatment.

2. The method for manufacturing the semiconductor device according to claim 1,

wherein a gate electrode and a gate insulating layer over the gate electrode are formed over the substrate before the first heat treatment, and

wherein the oxide semiconductor film is formed over the gate insulating layer.

3. The method for manufacturing the semiconductor device according to claim 1,

wherein the oxide semiconductor film contains indium and zinc.

4. The method for manufacturing the semiconductor device according to claim 1,

wherein the oxide semiconductor film includes crystals which are c-axis-oriented in a direction substantially perpendicular to a surface of the oxide semiconductor film after the second heat treatment.

5. The method for manufacturing the semiconductor device according to claim 1,

wherein moisture remaining on the inner wall of the chamber and moisture remaining in the target are removed by the first heat treatment.

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

performing a first heat treatment in a chamber in which a substrate and a target are provided;

forming an oxide semiconductor film over the substrate by sputtering method using the target; and

performing a second heat treatment on the oxide semiconductor film,

wherein the first heat treatment is performed at a temperature from 200°

C. to 600°

C.,

wherein the oxide semiconductor film is formed in the chamber without exposure to air after the first heat treatment,

wherein moisture remaining on an inner wall of the chamber and in the target is reduced by the first heat treatment, and

wherein hydrogen or moisture in the oxide semiconductor film is reduced by the second heat treatment.

7. The method for manufacturing the semiconductor device according to claim 6,

wherein the first heat treatment is performed under a reduced pressure.

8. The method for manufacturing the semiconductor device according to claim 6,

wherein a gate electrode and a gate insulating layer over the gate electrode are formed over the substrate before the first heat treatment, and

wherein the oxide semiconductor film is formed over the gate insulating layer.

9. The method for manufacturing the semiconductor device according to claim 6,

wherein the oxide semiconductor film contains indium and zinc.

10. The method for manufacturing the semiconductor device according to claim 6,

wherein the oxide semiconductor film includes crystals which are c-axis-oriented in a direction substantially perpendicular to a surface of the oxide semiconductor film after the second heat treatment.

11. The method for manufacturing the semiconductor device according to claim 6,

wherein moisture remaining on the inner wall of the chamber and moisture remaining in the target are removed by the first heat treatment.

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

performing a first heat treatment in a chamber in which a substrate and a target are provided;

forming an oxide semiconductor film over the substrate by sputtering method using the target; and

performing a second heat treatment on the oxide semiconductor film,

wherein the oxide semiconductor film is formed in the chamber without exposure to air after the first heat treatment,

wherein moisture remaining on an inner wall of the chamber and in the target is reduced by the first heat treatment,

wherein moisture remaining in the chamber is reduced by a cryopump before, during or after forming the oxide semiconductor film, and

wherein hydrogen or moisture in the oxide semiconductor film is reduced by the second heat treatment.

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

wherein inert gas is introduced into the chamber and then exhausted from the chamber during the first heat treatment.

14. The method for manufacturing the semiconductor device according to claim 12,

wherein a gate electrode and a gate insulating layer over the gate electrode are formed over the substrate before the first heat treatment, and

wherein the oxide semiconductor film is formed over the gate insulating layer.

15. The method for manufacturing the semiconductor device according to claim 12,

wherein the oxide semiconductor film contains indium and zinc.

16. The method for manufacturing the semiconductor device according to claim 12,

wherein the oxide semiconductor film includes crystals which are c-axis-oriented in a direction substantially perpendicular to a surface of the oxide semiconductor film after the second heat treatment.

17. The method for manufacturing the semiconductor device according to claim 12,

wherein moisture remaining on the inner wall of the chamber and moisture remaining in the target are removed by the first heat treatment, and

wherein moisture remaining in the chamber is removed by the cryopump before, during or after forming the oxide semiconductor film.