Transistor including indium in vicinity of interface between insulating films

• US 10,490,572 B2
• Filed: 05/01/2017
• Issued: 11/26/2019
• Est. Priority Date: 06/20/2014
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Okazaki, Kenichi, Koezuka, Junichi, Jintyou, Masami, Iguchi, Takahiro
• Primary Examiner(s): Tran, Tan N
• Application Number:
  US15/582,887
• Publication Number:
  US 20170236845A1
• Time in Patent Office: 939 Days
• 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 29/4908 for thin film semiconductor, e.g. gate of TFT
• CPC Class Codes: H01L 29/513 the variation being perpendicular to the channel plane
• 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 29/78609 for preventing leakage current H01L29/78618 takes 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
• 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

A change in electrical characteristics can be inhibited and reliability can be improved in a semiconductor device including an oxide semiconductor. The semiconductor device including an oxide semiconductor film includes a first insulating film, the oxide semiconductor film over the first insulating film, a second insulating film over the oxide semiconductor film, and a third insulating film over the second insulating film. The second insulating film includes oxygen and silicon, the third insulating film includes nitrogen and silicon, and indium is included in a vicinity of an interface between the second insulating film and the third insulating film.

Claims

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

forming a first insulating film;

forming an oxide semiconductor film over the first insulating film;

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

forming a third insulating film over the second insulating film,

wherein indium is included in a vicinity of an interface between the second insulating film and the third insulating film, and

wherein a concentration of indium at the interface is higher than a concentration of indium at a center of the second insulating film.

2. The method according to claim 1, wherein indium in the vicinity of the interface is measured by secondary ion mass spectrometry.

3. The method according to claim 1,

wherein the oxide semiconductor film comprises indium, zinc, and a metal, and

wherein the metal element is selected from at least one of titanium, gallium, tin, yttrium, zirconium, lanthanum, cerium, neodymium, and hafnium.

4. The method according to claim 1,

wherein the second insulating film comprises oxygen and silicon, and

wherein the third insulating film comprises nitrogen and silicon.

5. The method according to claim 1, wherein a concentration of indium in the vicinity of the interface is greater than or equal to 5×

10¹⁶ atoms/cm³.

6. The method according to claim 1, wherein the second insulating film is in contact with a channel formation region in the oxide semiconductor film.

7. The method according to claim 1, further comprising steps of:

forming a gate electrode; and

forming a source electrode and a drain electrode electrically connected to the oxide semiconductor film.

8. A method for manufacturing a semiconductor device comprising a transistor, the method comprising steps of:

forming a first insulating film;

forming an oxide semiconductor film over the first insulating film;

forming a second insulating film over the oxide semiconductor film;

forming a film comprising indium over the second insulating film; and

adding oxygen to the oxide semiconductor film and the second insulating film through the film comprising indium;

removing the film comprising indium; and

forming a third insulating film over the second insulating film after removing the film comprising indium,

wherein indium is included in a vicinity of an interface between the second insulating film and the third insulating film, and

wherein a concentration of indium at the interface is higher than a concentration of indium at a center of the second insulating film.

9. The method according to claim 8, wherein the addition of oxygen is performed by an ion doping method, an ion implantation method, or plasma treatment.

10. The method according to claim 8, wherein the addition of oxygen is performed at a substrate temperature of higher than or equal to a room temperature and lower than or equal to 300°

C.

11. The method according to claim 8, wherein the film comprising indium further comprises tin and silicon.

12. The method according to claim 8, wherein indium in the vicinity of the interface is measured by secondary ion mass spectrometry.

13. The method according to claim 8,

wherein the oxide semiconductor film comprises indium, zinc, and a metal, and

wherein the metal element is selected from at least one of titanium, gallium, tin, yttrium, zirconium, lanthanum, cerium, neodymium, and hafnium.

14. The method according to claim 8,

wherein the second insulating film comprises oxygen and silicon, and

wherein the third insulating film comprises nitrogen and silicon.

15. The method according to claim 8, wherein a concentration of indium in the vicinity of the interface is greater than or equal to 5×

10¹⁶ atoms/cm³.

16. The method according to claim 8, wherein the second insulating film is in contact with a channel formation region in the oxide semiconductor film.

17. The method according to claim 8, further comprising steps of:

forming a gate electrode; and

forming a source electrode and a drain electrode electrically connected to the oxide semiconductor film.

18. A method for manufacturing a semiconductor device comprising a transistor, the method comprising steps of:

forming a first insulating film;

forming an oxide semiconductor film over the first insulating film;

forming a second insulating film over the oxide semiconductor film;

forming a film comprising indium over the second insulating film; and

removing the film comprising indium; and

forming a third insulating film over the second insulating film after removing the film comprising indium,

wherein indium is included in a vicinity of an interface between the second insulating film and the third insulating film, and

wherein a concentration of indium at the interface is higher than a concentration of indium at a center of the second insulating film.

19. The method according to claim 18, wherein the film comprising indium further comprises tin and silicon.

20. The method according to claim 18, wherein indium in the vicinity of the interface is measured by secondary ion mass spectrometry.

21. The method according to claim 18,

wherein the oxide semiconductor film comprises indium, zinc, and a metal, and

wherein the metal element is selected from at least one of titanium, gallium, tin, yttrium, zirconium, lanthanum, cerium, neodymium, and hafnium.

22. The method according to claim 18,

wherein the second insulating film comprises oxygen and silicon, and

wherein the third insulating film comprises nitrogen and silicon.

23. The method according to claim 18, wherein a concentration of indium in the vicinity of the interface is greater than or equal to 5×

10¹⁶ atoms/cm³.

24. The method according to claim 18, wherein the second insulating film is in contact with a channel formation region in the oxide semiconductor film.

25. The method according to claim 18, further comprising steps of:

forming a gate electrode; and

forming a source electrode and a drain electrode electrically connected to the oxide semiconductor film.