System and method for mass-production of high-efficiency photovoltaic structures

1. A method for fabricating a photovoltaic structure, comprising:

forming a sacrificial layer on a first side of a Si substrate;

loading the Si substrate into a chemical vapor deposition tool, with the sacrificial layer in contact with a wafer carrier;

forming a first doped Si layer on a second side of the Si substrate;

subsequent to forming the first doped Si layer, removing the sacrificial layer that has been in contact with the wafer carrier;

loading the Si substrate into the chemical vapor deposition tool; and

forming a second doped Si layer on the first side of the Si substrate.

2. The method of claim 1 , wherein forming the sacrificial layer involves one or more operations selected from a group consisting of:

wet oxidation to form an oxide layer;

thermal oxidation to form an oxide layer;

low-pressure radical oxidation to form an oxide layer;

atomic layer deposition to form an oxide layer or a semiconductor layer; and

chemical-vapor deposition to form an oxide layer or a semiconductor layer.

3. The method of claim 1 , wherein a thickness of the sacrificial layer is between 1 and 50 angstroms.

4. The method of claim 1 , further comprising:

performing a quick dump rinsing operation prior to removing the sacrificial layer.

5. The method of claim 1 , wherein the sacrificial layer includes an oxide layer, and wherein removing the sacrificial layer involves performing a diluted hydrofluoric acid dip.

6. The method of claim 5 , wherein a concentration of the diluted hydrofluoric acid is between 0.1 and 5%.

7. The method of claim 1 , further comprising:

forming a passivation layer positioned between the Si substrate and the first doped Si layer, wherein the passivation layer includes one or more materials selected from a group consisting of:

aluminum oxide;

amorphous Si;

amorphous SiC; and

intrinsic hydrogenated amorphous Si incorporated with oxygen.

8. The method of claim 1 , further comprising:

forming a passivation layer positioned between the Si substrate and the second doped Si layer, wherein the passivation layer includes one or more materials selected from a group consisting of:

aluminum oxide;

amorphous Si;

amorphous SiC; and

intrinsic hydrogenated amorphous Si incorporated with oxygen.

9. The method of claim 1 , wherein the first doped Si layer has a graded doping profile, and wherein a doping concentration of the first doped Si layer near a surface away from the Si substrate is greater than 3×10 19 /cm 3 .

10. The method of claim 1 , further comprising one or more operations selected from a group consisting of:

forming a transparent conductive oxide layer on the first doped Si layer; and

forming a transparent conductive oxide layer on the second doped Si layer.

11. A fabrication system, comprising:

a first wet station configured to form a sacrificial layer on a first side of a plurality of photovoltaic structures;

a first chemical vapor deposition tool configured to deposit a first doped Si layer on a second side of the photovoltaic structures, wherein a wafer carrier associated with the first vapor deposition tool is in contact with the sacrificial layer;

a second wet station configured to remove the sacrificial layer; and

a second chemical vapor deposition tool configured to deposit a second doped Si layer on the first side of the photovoltaic structures, wherein during deposition, a wafer carrier associated with the second vapor deposition tool is facing the first doped Si layer.

12. The system of claim 11 , wherein while forming the sacrificial layer, the first wet station is configured to perform a wet oxidation process to form an oxide layer on the first side of the photovoltaic structures.

13. The system of claim 12 , wherein while removing the sacrificial layer, the second wet station is configured to perform a diluted hydrofluoric acid dip.

14. The system of claim 13 , wherein a concentration of the diluted hydrofluoric acid is between 0.1 and 5%.

15. The system of claim 11 , wherein a thickness of the sacrificial layer is between 1 and 50 angstroms.

16. The system of claim 11 , wherein the second wet station is further configured to perform a quick dump rinsing operation prior to removing the sacrificial layer.

17. The system of claim 11 , wherein the first chemical vapor deposition tool is further configured to form a passivation layer positioned between the Si substrate and the first doped Si layer, wherein the passivation layer includes one or more materials selected from a group consisting of:

aluminum oxide;

amorphous Si;

amorphous SiC; and

intrinsic hydrogenated amorphous Si incorporated with oxygen.

18. The system of claim 11 , wherein the second chemical vapor deposition tool is further configured to form a passivation layer positioned between the Si substrate and the second doped Si layer, wherein the passivation layer includes one or more materials selected from a group consisting of:

aluminum oxide;

amorphous Si;

amorphous SiC; and

intrinsic hydrogenated amorphous Si incorporated with oxygen.

19. The system of claim 11 , wherein the first doped Si layer has a graded doping profile, and wherein a doping concentration of the first doped Si layer near a surface away from the Si substrate is greater than 3×10 19 /cm 3 .

20. The system of claim 11 , further comprising a physical vapor deposition tool configured to perform one or more operations selected from a group consisting of:

forming a transparent conductive oxide layer on the first doped Si layer; and

forming a transparent conductive oxide layer on the second doped Si layer.