Method for producing smooth indium-tin-oxide layers on substrates and a substrate coating of indium-tin-oxide
In a method for producing ITO layers on substrates, especially for the production of organic light-emitting diodes, part of the ITO layer thickness is applied first by sputter-deposition, at a controlled temperature profile, in such manner that the formation of crystallization nuclei is prevented; subsequently, the partially coated substrate is heated to a temperature above the recrystallization temperature of the ITO layer, and then the rest of the ITO layer is sputter-deposited.
1. A method of producing smooth metal oxide layers, wherein a transparent conducting indium tin oxide (ITO) layer is applied onto a glass substrate to form an electrode, said method comprising:
sputter-depositing part of the ITO layer at a temperature profile controlled such that the formation of crystallization nuclei is prevented;
heating the substrate to a temperature above a recrystallization temperature of the ITO layer; and
sputter-depositing the rest of the ITO layer.
2. A method as recited in claim 1 , wherein the thickness of the first sputter-deposited ITO layer is less than 70 nm.
3. A method as recited in claim 2 , wherein the thickness of the first sputter-deposited ITO layer is in the range of 25 nm to 50 nm.
4. A method as recited in claim 1 , wherein sputtering is effected by a DC magnetron process.
5. A method as recited in claim 1 , wherein sputtering is effected by a RF/DC-pulsed magnetron process.
6. A method as recited in claim 1 , wherein the first ITO layer is sputter-deposited onto a substrate having a temperature below 150° C.
7. A method as recited in claim 6 , wherein the substrate has a temperature below approximately 100° C.
8. A method as recited in claim 1 , wherein the step of heating the partially coated substrate heats the substrate to a temperature of at least 150° C.
9. A method as recited in claim 8 , wherein the substrate is heated to a temperature of at least 180° C.
10. A method as recited in claim 2 , wherein the first ITO layer is sputter-deposited onto a substrate having a temperature below 150° C.
11. A method as recited in claim 10 , wherein the step of heating the partially coated substrate heats the substrate to a temperature of at least 150° C.
12. A method as recited in claim 3 , wherein the first ITO layer is sputter-deposited onto a substrate having a temperature below approximately 100° C.
13. A method as recited in claim 12 , wherein the step of heating the partially coated substrate heats the substrate to a temperature of at least 180° C.
14. A method as recited in claim 1 , wherein said method is used for the production of light-emitting diodes.
15. A substrate coating of indium tin oxide (ITO), said substrate coating comprising a first ITO layer having a thickness of less than 70 nm, and a second ITO layer applied on top of said first ITO layer, wherein said first ITO layer is crystallization free, and wherein said substrate coating is formed by a method comprising:
sputter-depositing said first ITO layer onto a substrate at a temperature profile controlled such that the formation of crystallization nuclei is prevented;
heating the substrate to a temperature above a recrystallization temperature of the ITO layer; and
sputter-depositing said second ITO layer on top of said first ITO layer.
16. The substrate coating of indium tin oxide according to claim 15 , wherein the first ITO layer is sputter-deposited onto a substrate having a temperature below 150° C.
17. The substrate coating of indium tin oxide according to claim 16 , wherein the step of heating the partially coated substrate heats the substrate to a temperature of at least 150° C.
18. The substrate coating of indium tin oxide according to claim 15 , wherein said substrate coating is used in the production of light-emitting diodes.
19. An organic light-emitting diode having a smooth indium tin oxide layer, wherein said smooth indium tin oxide layer is formed by a method comprising:
sputter-depositing a first ITO layer onto a substrate at a temperature profile controlled such that the formation of crystallization nuclei is prevented;
heating the substrate to a temperature above a recrystallization temperature of the ITO layer; and
sputter-depositing a second ITO layer on top of the first ITO layer.
20. The organic light-emitting diode of claim 19 , wherein the thickness of the first ITO layer is less than 70 nm.
21. The organic light-emitting diode of claim 20 , wherein the first ITO layer is sputter-deposited onto a substrate having a temperature below 150° C.
22. The organic light-emitting diode of claim 21 , wherein the step of heating the partially coated substrate heats the substrate to a temperature of at least 150° C.