Method for forming oxide semiconductor film and method for manufacturing semiconductor device

• US 9,209,267 B2
• Filed: 06/09/2015
• Issued: 12/08/2015
• Est. Priority Date: 11/30/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Ito, Daigo, Sato, Yuichi, Noda, Kosei
• Primary Examiner(s): PARKER, ALLEN L
• Application Number:
  US14/734,492
• Publication Number:
  US 20150311074A1
• Time in Patent Office: 182 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/265 producing ion implantation
• CPC Class Codes: H01L 29/66477 with an insulated gate, i.e. MISFET
• 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

Abstract

An oxide semiconductor film is formed over a substrate. A sacrifice film is formed to such a thickness that the local maximum of the concentration distribution of an injected substance injected into the oxide semiconductor film in the depth direction of the oxide semiconductor film is located in a region from an interface between the substrate and the oxide semiconductor film to a surface of the oxide semiconductor film. Oxygen ions are injected as the injected substance into the oxide semiconductor film through the sacrifice film at such an acceleration voltage that the local maximum of the concentration distribution of the injected substance in the depth direction of the oxide semiconductor film is located in the region, and then the sacrifice film is removed. Further, a semiconductor device is manufactured using the oxide semiconductor film.

Claims

1. A method for forming an oxide semiconductor film comprising the steps of:

forming an oxide semiconductor film over a substrate;

forming a sacrifice film over the oxide semiconductor film;

injecting oxygen ions into the oxide semiconductor film through the sacrifice film; and

completely removing the sacrifice film after injecting oxygen ions into the oxide semiconductor film,

wherein the sacrifice film is formed using the same material as the oxide semiconductor film.

2. The method for forming an oxide semiconductor film according to claim 1,

wherein the oxide semiconductor film is formed to a thickness greater than or equal to 5 nm and less than or equal to 50 nm, and

wherein the sacrifice film is formed to a thickness greater than or equal to 20 nm and less than or equal to 500 nm.

3. The method for forming an oxide semiconductor film according to claim 1,

wherein the oxygen ions are injected so that an amount of change in a concentration distribution of injected oxygen ions in a depth direction of the oxide semiconductor film is 40% or less on the basis of a concentration at a local maximum of the concentration distribution of the injected oxygen ions.

4. The method for forming an oxide semiconductor film according to claim 1,

wherein the sacrifice film is removed by any one of wet etching, dry etching, and chemical mechanical polishing.

5. The method for forming an oxide semiconductor film according to claim 1,

wherein the sacrifice film has such a thickness that a local maximum of a concentration distribution of the oxygen ions injected into the oxide semiconductor film in a depth direction of the oxide semiconductor film is located in a region from an interface between the substrate and the oxide semiconductor film to a surface of the oxide semiconductor film, and

wherein oxygen ions are injected into the oxide semiconductor film at such an acceleration voltage that the local maximum of the concentration distribution of injected oxygen ions in the depth direction of the oxide semiconductor film is located in the region.

6. The method for forming an oxide semiconductor film according to claim 1,

wherein oxygen ions are injected by an ion implantation method or an ion doping method.

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

forming an oxide semiconductor film over a substrate having an insulating surface;

forming a sacrifice film over the oxide semiconductor film;

injecting oxygen ions into the oxide semiconductor film through the sacrifice film;

removing the sacrifice film after injecting oxygen ions into the oxide semiconductor film;

forming an island-shaped oxide semiconductor film by processing the oxide semiconductor film into which the oxygen ions are injected;

forming a gate insulating film over the island-shaped oxide semiconductor film;

forming a gate electrode over the gate insulating film so as to overlap with the island-shaped oxide semiconductor film with the gate insulating film positioned between the gate electrode and the island-shaped oxide semiconductor film;

partly exposing the island-shaped oxide semiconductor film by processing the gate insulating film; and

forming a source electrode and a drain electrode over the partly exposed island-shaped oxide semiconductor film,

wherein the sacrifice film is formed using the same material as the oxide semiconductor film.

8. The method for manufacturing a semiconductor device according to claim 7,

wherein the oxide semiconductor film formed over the substrate having the insulating surface is formed to a thickness greater than or equal to 5 nm and less than or equal to 50 nm, and

wherein the sacrifice film is formed to a thickness greater than or equal to 20 nm and less than or equal to 500 nm.

9. The method for manufacturing a semiconductor device according to claim 7,

wherein the oxygen ions are injected so that an amount of change in a concentration distribution of injected oxygen ions in a depth direction of the oxide semiconductor film is 40% or less on the basis of a concentration at a local maximum of the concentration distribution of the injected oxygen ions.

10. The method for manufacturing a semiconductor device according to claim 7,

wherein the sacrifice film is removed by any one of wet etching, dry etching, and chemical mechanical polishing.

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

forming a base insulating film over the substrate, and

performing heat treatment after forming the gate insulating film so that oxygen is diffused into a region from an interface between the base insulating film and the oxide semiconductor film to a surface of the oxide semiconductor film,

wherein either or both of the gate insulating film and the base insulating film is formed using an oxide insulating film from which part of oxygen is released by heat treatment.

12. The method for manufacturing a semiconductor device according to claim 7,

wherein the sacrifice film has such a thickness that a local maximum of a concentration distribution of the oxygen ions injected into the oxide semiconductor film in a depth direction of the oxide semiconductor film is located in a region from an interface between the substrate and the oxide semiconductor film to a surface of the oxide semiconductor film, and

wherein oxygen ions are injected into the oxide semiconductor film at such an acceleration voltage that the local maximum of the concentration distribution of injected oxygen ions in the depth direction of the oxide semiconductor film is located in the region.

13. The method for forming an oxide semiconductor film according to claim 7,

wherein oxygen ions are injected by an ion implantation method or an ion doping method.