Processing method for group IBIIIAVIA semiconductor layer growth
View Patent ↗A method of forming a doped Group IBIIIAVIA absorber layer for solar cells by reacting a partially reacted precursor layer with a dopant structure. The precursor layer including Group IB, Group IIIA and Group VIA materials such as Cu, Ga, In and Se are deposited on a base and partially reacted. After the dopant structure is formed on the partially reacted precursor layer, the dopant structure and partially reacted precursor layer is fully reacted. The dopant structure includes a dopant material such as Na.
1. A process of forming a doped Group IBIIIAVIA absorber layer on a base, comprising:
depositing at least one Group IB and Group IIIA and VIA material on the base;
forming a partially reacted precursor layer by partially reacting the at least one Group IB and Group IIIA materials with at least one Group VIA material, wherein partially reacting the at least one Group IB and Group IIIA materials with at least one Group VIA material results in the partially reacted precursor layer having at least 50% non-metallic phase;
depositing a dopant-bearing film on the partially reacted precursor layer, the dopant-bearing film comprising a dopant material including at least one of Na, K and Li; and
fully reacting the partially reacted precursor layer with the dopant material from the dopant-bearing film to form the doped Group IBIIIAVIA absorber layer.
2. The process of claim 1 , wherein the Group IB material is Cu, Group IIIA materials are In and Ga, and at least one Group VIA material comprises Se.
3. The process of claim 2 further comprising supplying a gaseous environment containing Se during the step of fully reacting.
4. The process of claim 2 further comprising supplying a gaseous environment containing S during the step of fully reacting.
5. The process of claim 2 further comprising supplying a gaseous environment containing S during the step of partially reacting.
6. The process of claim 2 further comprising supplying a gaseous environment containing S and Se during the step of fully reacting.
7. The process of claim 1 , wherein the step of partially reacting comprises annealing at a temperature range of 250-550° C. for about 1-60 minutes.
8. The process of claim 1 , wherein the step of fully reacting comprises annealing at a temperature range of 400-600° C. for about 5-60 minutes.
9. The process of claim 1 , wherein the at least one Group IB, Group IIIA and Group VIA material comprise Cu, In, Ga and Se elements.
10. The process of claim 1 , wherein the step of depositing the at least one Group IB, Group IIIA, and Group VIA material on the base comprises electroplating.
11. The process of claim 1 , wherein the step of depositing the dopant-bearing film comprises dip coating the dopant material.
12. The process of claim 1 , wherein the step of depositing the dopant-bearing film comprises vapor depositing the dopant material.
13. The process of claim 1 , wherein the step of partially reacting the at least one Group IB and Group IIIA materials with at least one Group VIA material results in the partially reacted precursor layer having at least 80% non-metallic phase.
14. The process of claim 1 , wherein the non-metallic phase comprises at least one of selenides and sulfides of Cu, In, Ga, CuIn, CuGa, InGa, and CuInGa.
15. The process of claim 13 , wherein the non-metallic phase comprises at least one of selenides and sulfides of Cu, In, Ga, CuIn, CuGa, InGa, and CuInGa.