Consumable adhesive layer for thin film photovoltaic material
View Patent ↗A method for forming a thin film photovoltaic device may include providing a transparent substrate and forming a multi layered structure including at least a thin layer of indium material, copper material, and another layer of indium. A heat treatment may be performed that consumes substantially all of the thin layer of indium material into a portion of a copper indium disulfide alloy material. The method causes formation of a copper sulfide material overlying the copper indium disulfide alloy material during at least the thermal treatment process.
1. A method for forming a thin film photovoltaic device, the method comprising:
providing a substrate at a first station, the substrate comprising a surface region;
forming a first electrode layer on the surface region;
moving the substrate to a second station;
forming an adhesive layer over the first electrode layer at the second station;
forming a copper layer overlying the adhesive layer;
forming an indium layer over the copper layer to form a multilayered structure, the multilayered structure comprising the adhesive layer, the copper layer and the indium layer;
exposing the multilayered structure to an environment comprising sulfur bearing species;
forming a copper indium disulphide alloy material;
forming a cap layer comprising copper sulphide material overlying the copper indium disulphide alloy material;
removing a portion of the cap layer; and
forming a window layer overlying at least a portion of the copper indium disulphide alloy material.
2. The method of claim 1 wherein the adhesive layer is characterized by a thickness of between 200 Angstroms and 500 Angstroms.
3. The method of claim 1 wherein forming the adhesive layer comprises flash sputtering an indium target with an argon gas.
4. The method of claim 1 further comprising maintaining a pressure at the second station at about 5 millitorr and less.
5. The method of claim 1 further comprising maintaining a pressure at the second station between 1 millitorr and 42 millitorr.
6. The method of claim 1 wherein prior to forming the copper layer, moving the substrate to a third station.
7. The method of claim 1 wherein the cap layer is substantially free from indium species.
8. The method of claim 1 wherein the adhesive layer is formed at 120 Watts DC for less than about ten seconds.
9. The method of claim 1 wherein the adhesive layer is formed at a temperature ranging from about 50 Degrees Celsius to about 110 Degrees Celsius.
10. The method of claim 1 wherein removing the portion of the cap layer comprises exposing the cap layer to a solution including potassium cyanide.
11. A method comprising:
providing a substrate at a first station, the substrate comprising a surface region;
forming a first electrode layer on the surface region;
moving the substrate to a second station;
forming a first indium layer over the first electrode layer at the second station;
forming a copper layer overlying the adhesive layer;
forming a second indium layer over the copper layer to form a multilayered structure, the multilayered structure comprising the first indium layer, the copper layer and the second indium layer;
exposing the multilayered structure to an environment comprising sulfur bearing species;
consuming the first indium layer;
forming a copper indium disulphide alloy material;
forming a cap layer overlying the copper indium disulphide alloy material;
removing a portion of the cap layer; and
forming a window layer overlying at least a portion of the copper indium disulphide alloy material.
12. The method of claim 11 wherein the first indium layer is characterized by a thickness of between 200 Angstroms and 500 Angstroms.
13. The method of claim 11 wherein forming the first indium layer comprises flash sputtering an indium target with an argon gas.
14. The method of claim 11 wherein the cap layer comprises substantially of copper sulphide material.
15. The method of claim 11 wherein the first indium layer is between 25 nm and 100 nm thick, the copper layer is between 260 nm and 400 nm thick, and the second indium layer is between 413 nm and 473 nm thick.
16. The method of claim 11 wherein the copper indium disulphide alloy material has an atomic ratio of copper to indium ranging from about 1.35:1 to about 3:1.
17. The method of claim 11 wherein the multilayered structure is characterized by a first thickness and the copper indium disulphide alloy material is characterized by a second thickness, wherein the second thickness is more than twice the first thickness.
18. The method of claim 11 wherein the first indium layer is formed at 120 Watts DC for less than about ten seconds.
19. The method of claim 11 wherein the first indium layer is formed at a temperature ranging from about 50 Degrees Celsius to about 110 Degrees Celsius.
20. The method of claim 11 wherein the first indium layer is formed at a pressure of about 5 mtorr.