Semiconductor device and method for manufacturing the same

• US 10,243,064 B2
• Filed: 09/17/2015
• Issued: 03/26/2019
• 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
• Primary Examiner(s): Galvin, III, Joseph
• Application Number:
  US14/856,829
• Publication Number:
  US 20160013298A1
• Time in Patent Office: 1,286 Days
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/47635 After-treatment of these layers
• CPC Class Codes: H01L 21/477 Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering H01L21/38 - H01L21/449 and H01L21/461 - H01L21/475 take precedence
• CPC Class Codes: H01L 27/14632 Wafer-level processed structures
• CPC Class Codes: H01L 27/14687 Wafer level processing
• 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 29/24 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 29/66969 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

To provide a highly reliable semiconductor device by giving stable electrical characteristics to a transistor including an oxide semiconductor film. A gate electrode layer is formed over a substrate, a gate insulating film is formed over the gate electrode layer, an oxide semiconductor film is formed over the gate insulating film, a conductive film is formed over the oxide semiconductor film, so that a region in vicinity of an interface with the oxide semiconductor film in contact with the conductive film is made amorphous, heat treatment is performed, the conductive film is then processed to form a source electrode layer and a drain electrode layer, and a part of the amorphous region in the oxide semiconductor film which is exposed by formation of the source electrode layer and the drain electrode layer is removed.

Claims

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

forming a gate insulating film over a gate electrode;

forming an oxide semiconductor film over the gate insulating film, the oxide semiconductor film comprising indium, gallium, and zinc;

forming a conductive film over the oxide semiconductor film so that crystallinity of a first region of the oxide semiconductor film in contact with the conductive film is lowered, wherein the crystallinity of the first region is lower than crystallinity of a second region of the oxide semiconductor film, and wherein the second region is other than the first region and includes a channel region;

processing the conductive film to form a source electrode and a drain electrode so that a part of the first region is exposed by performing a first treatment;

removing part of the oxide semiconductor film so that the part of the first region is removed by performing a second treatment which is different from the first treatment; and

forming an insulating film over the oxide semiconductor film, the source electrode, and the drain electrode after removing the part of the first region, wherein the insulating film is in contact with the oxide semiconductor film at least between the source electrode and the drain electrode,

wherein the first treatment is performed using a mask,

wherein the second treatment is performed after removing the mask, and

wherein an atomic percentage of gallium is greater than or equal to an atomic percentage of indium in the second region.

2. The method according to claim 1, wherein the first region is amorphous.

3. The method according to claim 1, wherein, in the oxide semiconductor film, a proportion of a crystal part to an amorphous part in the first region is lower than a proportion of a crystal part to an amorphous part in the second region.

4. The method according to claim 1,

wherein the oxide semiconductor film includes a third region, a fourth region, and a fifth region,

wherein the third region overlaps with the source electrode,

wherein the fourth region overlaps with the drain electrode,

wherein the fifth region overlaps with neither the source electrode nor the drain electrode, and

wherein a thickness of the third region and a thickness of the fourth region are larger than a thickness of the fifth region.

5. The method according to claim 4,

wherein the fifth region is positioned between the third region and the fourth region in a channel length direction, and

wherein each of the third region and the fourth region is positioned between parts of the fifth region in a channel width direction.

6. The method according to claim 1, further comprising a step of:

performing heat treatment to the oxide semiconductor film.

7. The method according to claim 1, wherein the insulating film is in direct contact with the oxide semiconductor film at least between the source electrode and the drain electrode.

8. The method according to claim 1,

wherein the second treatment is a solution treatment using dilute hydrofluoric acid.

9. The method according to claim 1, wherein the conductive film is formed so that the first region is in direct contact with the conductive film.

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

forming a gate insulating film over a gate electrode;

forming an oxide semiconductor film over the gate insulating film, the oxide semiconductor film comprising indium, gallium, and zinc;

introducing an element to a surface of the oxide semiconductor film by ion implantation method, ion doping method or plasma treatment so that crystallinity of a first region of the oxide semiconductor film including the surface of the oxide semiconductor film is lowered, wherein the crystallinity of the first region is lower than crystallinity of a second region of the oxide semiconductor film, and wherein the second region is other than the first region and includes a channel region;

forming a source electrode and a drain electrode so that a part of the first region is exposed by performing a first treatment;

removing part of the oxide semiconductor film so that the part of the first region is removed by performing a second treatment which is different from the first treatment; and

forming an insulating film over the oxide semiconductor film, the source electrode, and the drain electrode after removing the part of the first region, wherein the insulating film is in contact with the oxide semiconductor film at least between the source electrode and the drain electrode,

wherein an atomic percentage of gallium is greater than or equal to an atomic percentage of indium in the second region.

11. The method according to claim 10, wherein the element is at least one selected from the group consisting of elements of Group 15,elements of Group 13 in the periodic table, and rare gas elements.

12. The method according to claim 10, wherein the first region is amorphous.

13. The method according to claim 10, wherein, in the oxide semiconductor film, a proportion of a crystal part to an amorphous part in the first region is lower than a proportion of a crystal part to an amorphous part in the second region.

14. The method according to claim 10,

wherein the oxide semiconductor film includes a third region, a fourth region, and a fifth region,

wherein the third region overlaps with the source electrode,

wherein the fourth region overlaps with the drain electrode,

wherein the fifth region overlaps with neither the source electrode nor the drain electrode, and

wherein a thickness of the third region and a thickness of the fourth region are larger than a thickness of the fifth region.

15. The method according to claim 14,

wherein the fifth region is positioned between the third region and the fourth region in a channel length direction, and

wherein each of the third region and the fourth region is positioned between parts of the fifth region in a channel width direction.

16. The method according to claim 10, further comprising a step of:

performing heat treatment to the oxide semiconductor film.

17. The method according to claim 10, wherein the insulating film is in direct contact with the oxide semiconductor film at least between the source electrode and the drain electrode.

18. The method according to claim 10,

wherein the first treatment is performed using a mask,

wherein the second treatment is performed after removing the mask, and

wherein the second treatment is a solution treatment using dilute hydrofluoric acid.

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

forming an oxide semiconductor film;

forming a conductive film over the oxide semiconductor film so that crystallinity of a first region of the oxide semiconductor film in contact with the conductive film is lowered, wherein the crystallinity of the first region is lower than crystallinity of a second region of the oxide semiconductor film, and wherein the second region is other than the first region and includes a channel region;

processing the conductive film to form a source electrode and a drain electrode so that a part of the first region is exposed by performing a first treatment; and

removing part of the oxide semiconductor film so that the part of the first region is removed by performing a second treatment which is different from the first treatment,

wherein the first treatment is performed using a mask, and

wherein the second treatment is performed after removing the mask.

20. The method according to claim 19, wherein the first region is amorphous.

21. The method according to claim 19, wherein, in the oxide semiconductor film, a proportion of a crystal part to an amorphous part in the first region is lower than a proportion of a crystal part to an amorphous part in the second region.

22. The method according to claim 19,

wherein the oxide semiconductor film includes a third region, a fourth region, and a fifth region,

wherein the third region overlaps with the source electrode,

wherein the fourth region overlaps with the drain electrode,

wherein the fifth region overlaps with neither the source electrode nor the drain electrode, and

wherein a thickness of the third region and a thickness of the fourth region are larger than a thickness of the fifth region.

23. The method according to claim 22,

wherein the fifth region is positioned between the third region and the fourth region in a channel length direction, and

wherein each of the third region and the fourth region is positioned between parts of the fifth region in a channel width direction.

24. The method according to claim 19, further comprising a step of:

performing heat treatment to the oxide semiconductor film.

25. The method according to claim 19, further comprising steps of:

forming a gate insulating film over a gate electrode and under the oxide semiconductor film; and

forming an insulating film over the oxide semiconductor film, the source electrode, and the drain electrode after removing the part of the first region, wherein the insulating film is in contact with the oxide semiconductor film at least between the source electrode and the drain electrode.