Zinc oxide-based transparent conductor and sputtering target for forming the transparent conductor
View Patent ↗Proposed is a zinc oxide-based transparent conductor characterized in having zinc oxide as its primary component, containing an element at 1 to 10 atomic % which has a smaller ion radius than zinc in the zinc oxide and serves as an n-type dopant for the zinc oxide, and containing nitrogen in which the atomicity ratio of nitrogen in relation to the n-type dopant (nitrogen/n-type dopant) is 0.3 to 0.6. In the development of a transparent conductor that does not contain In, which is an expensive raw material with concern of resource depletion, the limit of the conventional development technique known as the single-dopant method is exceeded, a guide to dopant selection as a specific means for realizing the co-doping theory is indicated, and a transparent conductor having low resistivity is provided.
1. A sputtering target for forming a zinc oxide-based transparent conductor comprising zinc oxide as its primary component, an element at 1 to 10 atomic % which has a smaller ion radius than zinc in the zinc oxide and serves as an n-type dopant for the zinc oxide, and containing nitrogen in which the atomicity ratio of nitrogen in relation to the n-type dopant (nitrogen/n-type dopant) is 0.3 to 0.6, and wherein the nitrogen is contained as gallium nitride.
2. The sputtering target for forming a zinc oxide-based transparent conductor according to claim 1 , wherein the element to serve as the n-type dopant is contained at 2 atomic % to 8 atomic %.
3. The sputtering target for forming a zinc oxide-based transparent conductor according to claim 2 , wherein the n-type dopant is gallium and/or aluminum.
4. The sputtering target for forming a zinc oxide-based transparent conductor according to claim 1 , wherein the n-type dopant is gallium or aluminum, or gallium and aluminum.
5. The sputtering target for forming a zinc oxide-based transparent conductor according to claim 1 , wherein the element to serve as the n-type dopant is contained at 2 atomic % to 8 atomic %.
6. The sputtering target for forming a zinc oxide-based transparent conductor according to claim 5 , wherein the n-type dopant is gallium or aluminum, or gallium and aluminum.
7. The sputtering target for forming a zinc oxide-based transparent conductor according to claim 1 , wherein the n-type dopant is gallium or aluminum, or gallium and aluminum.
8. A sputtering target for forming a transparent conductor, consisting of a sputtering target body consisting of zinc oxide as its primary component, 1 to 10 atomic % of an element which has a smaller ion radius than zinc in the zinc oxide and serves as an n-type dopant for the zinc oxide, and nitrogen in which the atomicity ratio of nitrogen in relation to the n-type dopant (number of atoms of nitrogen/number of atoms of the n-type dopant) is 0.3 to 0.6.
9. A sputtering target according to claim 8 , wherein the n-type dopant is gallium.
10. A sputtering target according to claim 9 , wherein nitrogen is contained as gallium nitride.
11. A sputtering target according to claim 10 , wherein the sputtering target body consists of a hot-pressed mixture of ZnO, Ga 2 O 3 and GaN powders.
12. A sputtering target according to claim 11 , wherein said sputtering target body is such that, when subjected to sputter-deposition, material deposited from said sputtering target body forms an n-type zinc oxide-based transparent conductor of low resistivity within a range of 0.18 to 0.85 mΩcm and of high transmittance of 90% or higher of light in the visible light region.
13. A sputtering target according to claim 8 , wherein the n-type dopant is aluminum.
14. A sputtering target according to claim 8 , wherein the n-type dopant is gallium and aluminum.
15. A sputtering target according to claim 14 , wherein nitrogen is contained as gallium nitride.
16. A sputtering target according to claim 15 , wherein the sputtering target body consists of a hot-pressed mixture of ZnO, Al 2 O 3 and GaN powders.
17. A sputtering target according to claim 16 , wherein said sputtering target body is such that, when subjected to sputter-deposition, material deposited from said sputtering target body forms an n-type zinc oxide-based transparent conductor of low resistivity within a range of 0.17 to 0.83 mΩcm and of high transmittance of 90% or higher of light in the visible light region.
18. A sputtering target according to claim 8 , wherein the element to serve as the n-type dopant is contained at 2 atomic % to 8 atomic %.