Method for forming metal oxide film, metal oxide film, and apparatus for forming metal oxide film
The present invention aims at providing a method for forming a metal oxide film which can further improve the production efficiency while maintaining low resistance of a metal oxide film formed thereby. In the method for forming a metal oxide film of the present invention, a solution ( 4 ) containing a metallic element and ammonia ( 4 a ) is formed into a mist. Meanwhile, a substrate ( 2 ) is heated. Then, the solution ( 4 ) formed into a mist is supplied onto a first main surface of the substrate ( 2 ) being heated.
1. A method for forming a metal oxide film, the method comprising:
(A) forming a solution comprising a metallic element and ammonia into a mist;
(B) heating a substrate, wherein the heating temperature is maintained at 300° C. or less; and
(C) supplying the mist from (A) onto a first main surface of the substrate from (B) to form a metal oxide film,
wherein the metal oxide film is a n-type semiconductor.
2. The method of claim 1 , further comprising:
(D) previously preparing data, which shows relationships between an ammonia content of the solution, a carrier concentration of the metal oxide film formed, and a mobility of the metal oxide film formed, prior to the forming (A); and
(E) determining the ammonia content of the solution with the data from (D), and preparing the solution comprising a determined ammonia content.
3. The method of claim 2 , wherein the metallic element is zinc, and
wherein (E) comprises preparing the solution in which a ratio of a number of moles of the ammonia to a number of moles of the zinc is more than 7.34.
4. The method of claim 2 , wherein the metallic element is zinc, and
wherein (E) comprises preparing the solution in which a number of moles of the ammonia per liter of the solution is more than 0.15 mol/L.
5. The method of claim 2 , wherein the metallic element is at least one selected from the group consisting of titanium, zinc, indium, and tin.
6. The method of claim 2 , wherein the supplying (C) comprises supplying the mist from (A) and ozone onto the first main surface of the substrate from (B).
7. The method of claim 1 , wherein
the metallic element is at least one selected from the group consisting of titanium, zinc, indium, and tin.
8. The method of claim 1 , wherein
the supplying (C) comprises supplying the mist from (A) and ozone onto the first main surface of the substrate from (B).
9. The method of claim 1 , wherein the metallic element comprises titanium and zinc.
10. The method of claim 1 , wherein the metallic element comprises titanium and indium.
11. The method of claim 1 , wherein the metallic element comprises titanium and tin.
12. The method of claim 1 , wherein the metallic element comprises zinc and indium.
13. The method of claim 1 , wherein the metallic element comprises zinc and tin.
14. The method of claim 1 , wherein the metallic element comprises indium and tin.
15. The method of claim 1 , wherein the metallic element comprises titanium, zinc, and indium.
16. The method of claim 1 , wherein the metallic element comprises titanium, zinc, and tin.
17. The method of claim 1 , wherein the metallic element comprises zinc, indium, and tin.
18. The method of claim 1 , wherein the metallic element comprises titanium, zinc, indium, and tin.
19. The method of claim 1 , wherein the metallic element is zinc.