Thin film semiconductor material produced through reactive sputtering of zinc target using nitrogen gases
The present invention generally comprises a semiconductor film and the reactive sputtering process used to deposit the semiconductor film. The sputtering target may comprise pure zinc (i.e., 99.995 atomic percent or greater), which may be doped with aluminum (about 1 atomic percent to about 20 atomic percent) or other doping metals. The zinc target may be reactively sputtered by introducing nitrogen and oxygen to the chamber. The amount of nitrogen may be significantly greater than the amount of oxygen and argon gas. The amount of oxygen may be based upon a turning point of the film structure, the film transmittance, a DC voltage change, or the film conductivity based upon measurements obtained from deposition without the nitrogen containing gas. The reactive sputtering may occur at temperatures from about room temperature up to several hundred degrees Celsius. After deposition, the semiconductor film may be annealed to further improve the film mobility.
1. A sputtering method, comprising:
disposing a zinc target in a sputtering chamber;
flowing a sputtering gas into the chamber, the sputtering gas comprising an oxygen containing gas and a nitrogen containing gas;
applying a bias to the target; and
depositing a semiconductor layer on a substrate, the semiconductor layer comprising the zinc, oxygen, and nitrogen and having a mobility greater than 20 cm 2 /V-s, wherein the oxygen containing gas and the nitrogen containing gas are flowed into the chamber at a flow ratio of nitrogen containing gas to oxygen containing gas in a range of about 10:1 to about 100:1.
2. The method of claim 1 , wherein the ratio is about 20:1.
3. The method of claim 1 , further comprising annealing the deposited semiconductor layer.
4. The method of claim 3 , wherein the zinc is doped with aluminum.
5. The method of claim 1 , wherein the oxygen containing gas is oxygen.
6. The method of claim 5 , wherein the nitrogen containing gas is nitrogen.
7. The method of claim 1 , wherein the substrate has a surface area greater than about 0.04 square meters.
8. The method of claim 1 , wherein the depositing occurs within a temperature range of about 25 degrees Celsius to about 50 degrees Celsius.
9. A sputtering method, comprising:
flowing a nitrogen containing gas and an oxygen containing gas into a sputtering chamber, the chamber having a metal target comprising zinc; and
sputter depositing a semiconductor layer onto a substrate, the semiconductor layer comprising zinc, oxygen, and nitrogen and having a mobility greater than 20 cm 2 /V-s, wherein the oxygen containing gas and the nitrogen containing gas are flowed into the chamber at a flow ratio of nitrogen containing gas to oxygen containing gas in a range of about 10:1 to about 100:1.
10. The method of claim 9 , wherein the ratio is about 20:1.
11. The method of claim 9 , further comprising annealing the deposited semiconductor layer.
12. The method of claim 11 , wherein the zinc is doped with aluminum.
13. The method of claim 9 , wherein the oxygen containing gas is oxygen.
14. The method of claim 13 , wherein the nitrogen containing gas is nitrogen.
15. The method of claim 9 , wherein the substrate has a surface area greater than about 0.04 square meters.
16. The method of claim 9 , wherein the depositing occurs within a temperature range of about 25 degrees Celsius to about 50 degrees Celsius.
17. The method of claim 16 , wherein the semiconductor layer comprises an oxynitride.
18. The method of claim 1 , wherein the semiconductor layer comprises an oxynitride.