In—Ga—Zn—O type sputtering target

• US 8,858,844 B2
• Filed: 11/16/2010
• Issued: 10/14/2014
• Est. Priority Date: 11/18/2009
• Status: Active Grant

• Current Assignee: Idemitsu Kosan Company Limited
• Original Assignee: Idemitsu Kosan Company Limited
• Inventors: Yano, Koki, Itose, Masayuki
• Primary Examiner(s): Nguyen, Khanh Tuan
• Application Number:
  US13/265,039
• Publication Number:
  US 20120118726A1
• Time in Patent Office: 1,428 Days
• Field of Search: 252/518.1, 252/520.1, 252/519.5, 204/192.25, 204/298.13
• US Class Current: 252/519.5
• CPC Class Codes: C04B 2235/3284 Zinc oxides, zincates, cadmium oxides, cadmiates, mercury oxides, mercurates or oxide forming salts thereof
• CPC Class Codes: C04B 2235/3286 Gallium oxides, gallates, indium oxides, indates, thallium oxides, thallates or oxide forming salts thereof, e.g. zinc gallate
• CPC Class Codes: C04B 2235/3293 Tin oxides, stannates or oxide forming salts thereof, e.g. indium tin oxide [ITO]
• CPC Class Codes: C04B 2235/5409 expressed by specific surface values
• CPC Class Codes: C04B 2235/604 Pressing at temperatures other than sintering temperatures
• CPC Class Codes: C04B 2235/656 characterised by specific heating conditions during heat treatment
• CPC Class Codes: C04B 2235/6562 Heating rate
• CPC Class Codes: C04B 2235/6565 Cooling rate
• CPC Class Codes: C04B 2235/6567 Treatment time
• CPC Class Codes: C04B 2235/6585 at an oxygen percentage above that of air
• CPC Class Codes: C04B 2235/664 Reductive annealing
• CPC Class Codes: C04B 2235/80 Phases present in the sintered or melt-cast ceramic products other than the main phase
• CPC Class Codes: C04B 2235/963 Surface properties, e.g. surface roughness
• CPC Class Codes: C04B 35/01 based on oxide ceramics
• CPC Class Codes: C04B 35/453 based on zinc, tin, or bismuth oxides or solid solutions thereof with other oxides, e.g. zincates, stannates or bismuthates
• CPC Class Codes: C04B 35/6261 Milling
• CPC Class Codes: C04B 35/62695 Granulation or pelletising devices for shaping artificial aggregates from ceramic mixtures B28B1/004
• CPC Class Codes: C23C 14/08 Oxides C23C14/10 takes precedence
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• CPC Class Codes: H01L 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02488 : Insulating materials
• CPC Class Codes: H01L 21/02554 : Oxides
• CPC Class Codes: H01L 21/02565 : Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02631 : Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• 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

A sputtering target including an oxide sintered body which includes In, Ga and Zn and includes a structure having a larger In content than that in surrounding structures and a structure having larger Ga and Zn contents than those in surrounding structures.

Claims

1. A sputtering target comprising an oxide sintered body which comprises In, Ga and Zn, and does not comprise Sn or comprises Sn at an atomic ratio [Sn/(In+Ga+Zn+Sn)] of less than 0.05, and comprises a structure having a larger In content than that in surrounding structures and a structure having larger Ga and Zn contents than those in surrounding structures.

2. The sputtering target according to claim 1, wherein the oxygen content in the structure having a larger In content is smaller than that in surrounding structures.

3. The sputtering target according to claim 1, wherein the structure having a larger In content has a continuous structure with a length of 15 μ

m or longer.

4. The sputtering target according to claim 1, wherein the oxide sintered body has a bixbyite structure represented by In₂O₃ and a homologous structure represented by InGaZnO₄.

5. The sputtering target according to claim 1, wherein the oxide sintered body comprises a bixbyite structure represented by In₂O₃ and a spinel structure represented by ZnGa₂O₄.

6. The sputtering target according to claim 1, wherein the oxide sintered body comprises a bixbyite structure represented by In₂O₃ and a homologous structure represented by In_1.5Ga_0.5Zn₂O₅.

7. The sputtering target according to claim 1, wherein the atomic ratio of In, Ga and Zn of the oxide sintered body satisfies the following formulas:

0.20≦

In/(In+Ga+Zn)≦

0.70

0.01≦

Ga/(In+Ga+Zn)≦

0.50

0.05≦

Zn/(In+Ga+Zn)≦

0.60.

8. The sputtering target according to claim 7, wherein the atomic ratio of In, Ga and Zn of the oxide sintered body satisfies the following formulas:

Ga/(In+Ga+Zn)≦

0.45

0.10≦

Zn/(In+Ga+Zn)≦

0.40

In/(In+Ga)<

0.60.

9. The sputtering target according to claim 7, wherein the atomic ratio of In, Ga and Zn of the oxide sintered body satisfies the following formulas:

In/(In+Ga+Zn)≦

0.65

0.10≦

Ga/(In+Ga+Zn)

0.10≦

Zn/(In+Ga+Zn)

0.60≦

In/(In+Ga)

0.51≦

In/(In+Zn).

10. The sputtering target according to claim 1, wherein the oxide sintered body further comprises Sn in an atomic ratio which satisfies the following formula:

0.0001<

Sn/(In+Ga+Zn+Sn)<

0.05.

11. The sputtering target according to claim 1, which consists essentially of In, Ga, Zn and O.

12. A method for producing the sputtering target according to claim 5, which comprises the step of sintering a shaped body which comprises an oxide comprising a spinel structure represented by ZnGa₂O₄.

13. A method for producing a semiconductor device comprising the step of forming an oxide film by using the sputtering target according to claim 1.

14. The sputtering target according to claim 2, wherein the structure having a larger In content has a continuous structure with a length of 15 μ

m or longer.

15. The sputtering target according to claim 2, wherein the oxide sintered body has a bixbyite structure represented by In₂O₃ and a homologous structure represented by InGaZnO₄.

16. The sputtering target according to claim 2, wherein the oxide sintered body comprises a bixbyite structure represented by In₂O₃ and a spinel structure represented by ZnGa₂O₄.

17. The sputtering target according to claim 2, wherein the oxide sintered body comprises a bixbyite structure represented by In₂O₃ and a homologous structure represented by In_1.5Ga_0.5Zn₂O₅.

18. The sputtering target according to claim 2, wherein the atomic ratio of In, Ga and Zn of the oxide sintered body satisfies the following formulas:

0.20≦

In/(In+Ga+Zn)≦

0.70

0.01≦

Ga/(In+Ga+Zn)≦

0.50

0.05≦

Zn/(In+Ga+Zn)≦

0.60.

19. The sputtering target according to claim 18, wherein the atomic ratio of In, Ga and Zn of the oxide sintered body satisfies the following formulas:

Ga/(In+Ga+Zn)≦

0.45

0.10≦

Zn/(In+Ga+Zn)≦

0.40

In/(In+Ga)<

0.60.

20. The sputtering target according to claim 18, wherein the atomic ratio of In, Ga and Zn of the oxide sintered body satisfies the following formulas:

In/(In+Ga+Zn)≦

0.65

0.10≦

Ga/(In+Ga+Zn)

0.10≦

Zn/(In+Ga+Zn)

0.60≦

In/(In+Ga)

0.51≦

In/(In+Zn).