Method of forming an indium-containing transparent conductive oxide film, metal targets used in the method and photovoltaic devices utilizing said films

• US 20100258180A1
• Filed: 02/04/2010
• Published: 10/14/2010
• Est. Priority Date: 02/04/2009
• Status: Abandoned Application

• Current Assignee: HelioVolt Corporation
• Original Assignee: HelioVolt Corporation
• Inventors: Eldada, Louay, Oswald, Robert, Deng, Yuepeng
• Application Number:
  US12/658,203
• Publication Number:
  US 20100258180A1
• Time in Patent Office: Days
• US Class Current: 136/256
• CPC Class Codes: C23C 14/0042 Controlling partial pressure or flow rate of reactive or inert gases with feedback of measurements
• CPC Class Codes: C23C 14/086 of zinc, germanium, cadmium, indium, tin, thallium or bismuth
• CPC Class Codes: H01L 31/1884 Manufacture of transparent electrodes, e.g. TCO, ITO
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

A method of forming an indium-containing transparent conductive oxide by reactive sputtering a metal target containing indium in an oxygen containing atmosphere and then depositing the resulting indium oxide on a substrate. Metal targets used in the method and photovoltaic devices utilizing the transparent conductive oxides are also disclosed.

Claims

1. A method of forming an indium-containing transparent conductive oxide film comprising:

a) reactive sputtering a metal target comprising indium in an oxygen-containing atmosphere to form an indium-containing oxide

b) depositing the indium oxide on a substrate to form said transparent conductive oxide film.

2. The method of claim 1 wherein the metal target further comprises a metal selected from the group consisting of zinc, gallium and aluminum and combinations thereof.

3. The method of claim 1 wherein the step of reactive sputtering comprises contacting the metal target with an inert gas under conditions sufficient to sputter the metal from the target.

4. The method of claim 3 wherein the inert gas is argon.

5. The method of claim 1 further comprising controlling the quantity of oxygen in the oxygen-containing atmosphere.

6. The method of claim 5 wherein the step of controlling the quantity of oxygen comprises monitoring a variable selected from the group consisting of voltage, O₂ partial pressure and O₂ plasma emission and associating the variable with the flow of oxygen.

7. The method of claim 1 wherein the metallic target is in the form of a rotatable cylinder.

8. The method of claim 1 wherein the metallic target is planar.

9. The method of claim 1 wherein the metal target comprises indium and zinc.

10. The method of claim 9 wherein the step of the reactive sputtering frees indium and zinc from the target.

11. The method of claim 9 wherein the target comprises In_xZn_1-x wherein x is in the range of from about 0.01 to 0.95.

12. The method of claim 11 wherein x is in the range of from about 0.6 to 0.9.

13. A photovoltaic device comprising a substrate, a transparent conductive layer and an absorber layer between the substrate and the transparent conductive layer, said transparent conductive layer formed by the method of claim 1.

14. The photovoltaic device of claim 13 wherein the metal target further comprises a metal selected from the group consisting of zinc, gallium and aluminum and combinations thereof.

15. The photovoltaic device of claim 13 wherein the step of reactive sputtering comprises contacting the metal target with an inert gas under conditions sufficient to free the metal atoms from the target surface.

16. The photovoltaic device of claim 15 wherein the inert gas is argon.

17. The photovoltaic device of claim 13 further comprising controlling the quantity of oxygen in the oxygen containing atmosphere.

18. The photovoltaic device of claim 17 wherein the step of controlling the quantity of oxygen comprises monitoring a variable from the group consisting of voltage, O₂ partial pressure and O₂ plasma emission and associating the variable with the flow of oxygen.

19. The photovoltaic device of claim 13 wherein the metallic target is in the form of a rotatable cylinder.

20. The photovoltaic device of claim 13 wherein the metallic target is planar.

21. The photovoltaic device of claim 13 wherein the metal target comprises indium and zinc.

22. The photovoltaic device of claim 13 wherein the target comprises In_xZn_1-x and wherein x is in the range of from about 0.01 to 0.95.

23. The photovoltaic device of claim 22 wherein x is in the range of from about 0.6 to 0.9.

24. The photovoltaic device of claim 13 further comprising a transparent resistive layer between the transparent conductive layer and absorber layer.

25. The photovoltaic device of claim 24 wherein the transparent resistive layer comprises an oxide selected from IGZO and IAZO.

26. The photovoltaic device of claim 13 having a light transmission rate of at least 85%.