METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

• US 20130196468A1
• Filed: 01/22/2013
• Published: 08/01/2013
• Est. Priority Date: 01/26/2012
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Granted Patent: US 8,956,912 B2
• Time in Patent Office: Days
• US Class Current: 438/104
• CPC Class Codes: H01L 27/1251 comprising TFTs having a different architecture, e.g. top- and bottom gate TFTs
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/36 characterised by the concentration or distribution of impurities in the bulk material within semiconductor regions H01L29/06
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT
• 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 29/78606 with supplementary region or layer in the thin film or in the insulated bulk substrate supporting it for controlling or increasing the safety of the device H01L29/78642, H01L29/78645 take precedence
• CPC Class Codes: H01L 29/78651 Silicon transistors H01L29/78606 - H01L29/78645 take precedence
• 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

To improve productivity of a transistor that includes an oxide semiconductor and has good electrical characteristics. In a top-gate transistor including a gate insulating film and a gate electrode over an oxide semiconductor film, a metal film is formed over the oxide semiconductor film, oxygen is added to the metal film to form a metal oxide film, and the metal oxide film is used as a gate insulating film. After an oxide insulating film is formed over the oxide semiconductor film, a metal film may be formed over the oxide insulating film. Oxygen is added to the metal film to form a metal oxide film and added also to the oxide semiconductor film or the oxide insulating film.

Claims

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

forming an oxide semiconductor film over an oxide insulating film;

forming a metal film covering the oxide semiconductor film;

forming a metal oxide film by adding oxygen to the metal film; and

forming a gate electrode over the metal oxide film.

2. The method for manufacturing a semiconductor device, according to claim 1, further comprising the steps of:

forming sidewall insulating films in contact with side surfaces of the gate electrode;

etching the metal oxide film not overlapping with the gate electrode and the sidewall insulating films; and

forming a pair of electrodes in contact with parts of the oxide semiconductor film and the sidewall insulating films which are exposed by the etching.

3. The method for manufacturing a semiconductor device, according to claim 1, wherein oxygen is added to the metal film and added also to the oxide semiconductor film.

4. The method for manufacturing a semiconductor device, according to claim 1, further comprising the steps of:

forming an oxide insulating film over the oxide semiconductor film; and

forming the metal film over the oxide insulating film, wherein oxygen is added to the metal film and added also to the oxide insulating film over the oxide semiconductor film.

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

wherein the metal film is an aluminum film, a hafnium film, or an yttrium film, and

wherein the metal oxide film is an oxide film or an oxynitride film corresponding to the metal film.

6. The method for manufacturing a semiconductor device, according to claim 1, further comprising the steps of:

forming low-resistance regions in the oxide semiconductor film by adding dopants to the oxide semiconductor film with use of the gate electrode as a mask after the gate electrode is formed; and

forming the sidewall insulating films over the oxide semiconductor film including the low-resistance regions.

7. The method for manufacturing a semiconductor device, according to claim 1, further comprising the steps of:

forming low-resistance regions in the oxide semiconductor film by adding dopants to the oxide semiconductor film with use of the gate electrode as a mask after the gate electrode is formed; and

forming the sidewall insulating films over the oxide semiconductor film including the low-resistance regions,

wherein the dopants are one or more of boron, nitrogen, phosphorus, and arsenic, and

wherein the dopants are contained in the low-resistance regions at a concentration of greater than or equal to 5×

10¹⁸ atoms/cm³ and smaller than or equal to 1×

10²² atoms/cm³

8. The method for manufacturing a semiconductor device, according to claim 1, further comprising the steps of:

forming low-resistance regions in the oxide semiconductor film by adding dopants to the oxide semiconductor film with use of the gate electrode as a mask after the gate electrode is formed; and

forming the sidewall insulating films over the oxide semiconductor film including the low-resistance regions,

wherein the dopants are one or more of helium, neon, argon, krypton, and xenon, and

wherein the dopants are contained in the low-resistance regions at a concentration of greater than or equal to 5×

10¹⁸ atoms/cm³ and smaller than or equal to 1×

10²² atoms/cm³

9. The method for manufacturing a semiconductor device, according to claim 1, wherein the oxide semiconductor film comprises one or more elements selected from In, Ga, Sn, and Zn.

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

forming an oxide semiconductor film over a first oxide insulating film;

forming a second oxide insulating film over the oxide semiconductor film;

forming a gate electrode over the second oxide insulating film;

forming sidewall insulating films in contact with side surfaces of the gate electrode;

etching part of the second oxide insulating film that does not overlap with the gate electrode and the sidewall insulating films;

forming a pair of electrodes in contact with parts of the oxide semiconductor film and the sidewall insulating films which are exposed by the etching;

forming a metal film covering the pair of electrodes and the gate electrode; and

forming a metal oxide film by adding oxygen to the metal film.

11. The method for manufacturing a semiconductor device, according to claim 10, further comprising the steps of:

forming a third oxide insulating film over the pair of electrodes and the gate electrode after the pair of electrodes is formed; and

forming the metal film covering the third oxide insulating film,

wherein oxygen is added to the metal film and added also to the third oxide insulating film.

12. The method for manufacturing a semiconductor device, according to claim 10,

wherein the metal film is an aluminum film, a hafnium film, or an yttrium film, and

wherein the metal oxide film is an oxide film or an oxynitride film corresponding to the metal film.

13. The method for manufacturing a semiconductor device, according to claim 10, further comprising the steps of:

forming low-resistance regions in the oxide semiconductor film by adding dopants to the oxide semiconductor film with use of the gate electrode as a mask after the gate electrode is formed; and

forming the sidewall insulating films over the oxide semiconductor film including the low-resistance regions.

14. The method for manufacturing a semiconductor device, according to claim 10, further comprising the steps of:

forming low-resistance regions in the oxide semiconductor film by adding dopants to the oxide semiconductor film with use of the gate electrode as a mask after the gate electrode is formed; and

forming the sidewall insulating films over the oxide semiconductor film including the low-resistance regions,

wherein the dopants are one or more of boron, nitrogen, phosphorus, and arsenic, and

wherein the dopants are contained in the low-resistance regions at a concentration of greater than or equal to 5×

10¹⁸ atoms/cm³ and smaller than or equal to 1×

10²² atoms/cm³

15. The method for manufacturing a semiconductor device, according to claim 10, further comprising the steps of:

forming low-resistance regions in the oxide semiconductor film by adding dopants to the oxide semiconductor film with use of the gate electrode as a mask after the gate electrode is formed; and

forming the sidewall insulating films over the oxide semiconductor film including the low-resistance regions,

wherein the dopants are one or more of helium, neon, argon, krypton, and xenon, and

wherein the dopants are contained in the low-resistance regions at a concentration of greater than or equal to 5×

10¹⁸ atoms/cm³ and smaller than or equal to 1×

10²² atoms/cm³

16. The method for manufacturing a semiconductor device, according to claim 10, wherein the oxide semiconductor film comprises one or more elements selected from In, Ga, Sn, and Zn.