Method for manufacturing a compound semiconductor solar cell

1. A method for manufacturing a compound semiconductor solar cell, comprising:

forming a sacrificial layer on one surface of a mother substrate;

forming a compound semiconductor layer on the sacrificial layer;

forming a first protective layer formed of a compound semiconductor on the compound semiconductor layer;

depositing a second passivation layer on the first passivation layer;

attaching a first lamination film on the second protective layer;

separating the compound semiconductor layer, the first and second protective layers, and the first lamination film from the mother substrate by performing an epitaxial lift off (ELO) process to remove the sacrificial layer;

forming a back electrode on the compound semiconductor layer;

attaching a second lamination film on the back electrode;

removing the first lamination film;

removing the second protective layer;

removing the first protective layer; and

forming a front electrode on the compound semiconductor layer.

2. The method for manufacturing a compound semiconductor solar cell of claim 1 , wherein a layer of the compound semiconductor layer that is in direct contact with the first passivation layer is formed of gallium arsenide (GaAs), and the first passivation layer is formed of a compound semiconductor other than the GaAs.

3. The method for manufacturing a compound semiconductor solar cell of claim 2 , wherein the first passivation layer is formed of any one compound semiconductor selected from gallium indium phosphide (GaInP), aluminum indium phosphide (AlInP), and aluminum gallium indium phosphide (AlGaInP).

4. The method for manufacturing a compound semiconductor solar cell of claim 3 , wherein the first passivation layer is removed with an etching solution containing hydrochloric acid (HCL).

5. The method for manufacturing a compound semiconductor solar cell of claim 1 , wherein the second passivation layer is formed of a first metal layer and a second metal layer formed of a metal different from the first metal layer.

6. The method for manufacturing a compound semiconductor solar cell of claim 5 , wherein the first metal layer is formed of copper (Cu), and the first metal layer is removed with an etching solution containing ammonium hydroxide (NH 4 OH) and hydrogen peroxide (H 2 O 2 ).

7. The method for manufacturing a compound semiconductor solar cell of claim 6 , wherein the second protective layer is formed to a thickness of 1 to 10 μm.

8. The method for manufacturing a compound semiconductor solar cell of claim 7 , wherein a thickness of the first metal layer is 80% or more of the thickness of the second protective layer.

9. The method for manufacturing a compound semiconductor solar cell of claim 7 , wherein the second metal layer is formed of at least one selected from silver (Ag), gold (Au), platinum (Pt), palladium (Pd), nickel (Ni), and molybdenum (Mo).

10. The method for manufacturing a compound semiconductor solar cell of claim 9 , wherein the second metal layer is removed with an etching solution comprising at least one of potassium iodide (KI) and potassium cyanide (H 2 O 2 ).

11. The method for manufacturing a compound semiconductor solar cell of claim 9 , wherein the second metal layer is formed between the first protective layer and the first metal layer, and/or between the first metal layer and the first lamination film.

12. The method for manufacturing a compound semiconductor solar cell of claim 11 , wherein at least two first metal layers are formed.

13. The method for manufacturing a compound semiconductor solar cell of claim 12 , wherein the second metal layer is further formed between the at least two first metal layers.

14. The method for manufacturing a compound semiconductor solar cell of claim 6 , wherein hydrofluoric acid (HF) is used as an etching solution in the ELO process.

15. The method for manufacturing a compound semiconductor solar cell of claim 6 , wherein the first lamination film and the second lamination film are respectively formed of a PET film serving as a supporting substrate and an EVA film positioned on one side of the PET film and acting as an adhesive.

16. The method for manufacturing a compound semiconductor solar cell of claim 15 , wherein the PET film and the EVA film are formed to a thickness of 25 to 75 μm, respectively.

17. The method for manufacturing a compound semiconductor solar cell of claim 16 , wherein the first lamination film and the second lamination film are attached at a temperature of 70 to 150° C., respectively.

18. The method for manufacturing a compound semiconductor solar cell of claim 16 , further comprising attaching a first carrier substrate on the first lamination film between the step of performing the ELO process and the step of forming the back electrode.

19. The method for manufacturing a compound semiconductor solar cell of claim 18 , further comprising attaching a second carrier substrate on the second lamination film and removing the first carrier substrate between the step of attaching the second lamination film and the step of removing the first lamination film.

20. The method for manufacturing a compound semiconductor solar cell of claim 19 , further comprising removing the second carrier substrate and removing the second lamination film after the step of forming the front electrode.