Solar cell having an emitter region with wide bandgap semiconductor material
Solar cells having emitter regions composed of wide bandgap semiconductor material are described. In an example, a method includes forming, in a process tool having a controlled atmosphere, a thin dielectric layer on a surface of a semiconductor substrate of the solar cell. The semiconductor substrate has a bandgap. Without removing the semiconductor substrate from the controlled atmosphere of the process tool, a semiconductor layer is formed on the thin dielectric layer. The semiconductor layer has a bandgap at least approximately 0.2 electron Volts (eV) above the bandgap of the semiconductor substrate.
1. A solar cell, comprising:
a semiconductor substrate;
a first thin dielectric layer disposed on the semiconductor substrate;
a first semiconductor region of a first conductivity type disposed on the first thin dielectric layer;
a second thin dielectric layer disposed on the semiconductor substrate; and
a second semiconductor region of a second conductivity type disposed on the second thin dielectric layer, the second conductivity type opposite the first conductivity type, wherein the second thin dielectric layer is disposed on a sidewall surface of the first semiconductor region, and the second dielectric layer laterally separates the first and second semiconductor regions.
2. The solar cell of claim 1 , wherein the first semiconductor region is a first polysilicon region, and the second semiconductor region is a second polysilicon region.
3. The solar cell of claim 1 , wherein the first thin dielectric layer is a first oxide layer, and the second thin dielectric layer is a second oxide layer.
4. The solar cell of claim 3 , wherein the first oxide layer and the second oxide layer comprise silicon.
5. The solar cell of claim 1 , wherein the second thin dielectric layer covers at least a portion of the first semiconductor region.
6. The solar cell of claim 1 , wherein the second thin dielectric layer and the second semiconductor region include a contact opening through which a metal contact is formed to contact to the first semiconductor region.
7. The solar cell of claim 1 , wherein the first conductivity type is N-type, and the second conductivity type is P-type.
8. The solar cell of claim 1 , wherein the first conductivity type is P-type, and the second conductivity type is N-type.
9. The solar cell of claim 1 , wherein the second semiconductor region has a dopant concentration approximately in the range of 1×10 17 -1×10 21 atoms/cm 3 .
10. The solar cell of claim 1 , further comprising:
an oxide layer disposed over a light receiving surface of the semiconductor substrate, the light receiving surface opposite the first thin dielectric layer and the second thin dielectric layer;
an amorphous silicon layer disposed on the oxide layer; and
an anti-reflective coating (ARC) layer disposed on the amorphous silicon layer, the ARC layer comprising silicon nitride.
11. A solar cell, comprising:
a silicon substrate;
a first dielectric layer on the silicon substrate;
a first silicon region of a first conductivity type on the first dielectric layer;
a second dielectric layer on the silicon substrate; and
a second silicon region of a second conductivity type on the second dielectric layer, the second conductivity type opposite the first conductivity type, wherein the second dielectric layer is on a sidewall surface of the first silicon region, and the second dielectric layer laterally separates the first and second silicon regions.
12. The solar cell of claim 11 , wherein the first silicon region is a first polysilicon region, and the second silicon region is a second polysilicon region.
13. The solar cell of claim 11 , wherein the first dielectric layer is a first oxide layer, and the second dielectric layer is a second oxide layer.
14. The solar cell of claim 13 , wherein the first oxide layer and the second oxide layer comprise silicon.
15. The solar cell of claim 11 , wherein the second dielectric layer covers at least a portion of the first silicon region.
16. The solar cell of claim 11 , wherein the second dielectric layer and the second silicon region include a contact opening through which a metal contact is formed to contact to the first silicon region.
17. The solar cell of claim 11 , wherein the first conductivity type is N-type, and the second conductivity type is P-type.
18. The solar cell of claim 11 , wherein the first conductivity type is P-type, and the second conductivity type is N-type.
19. The solar cell of claim 11 , wherein the second silicon region has a dopant concentration approximately in the range of 1×10 17 -1×10 21 atoms/cm 3 .
20. The solar cell of claim 11 , further comprising:
an oxide layer over a light receiving surface of the silicon substrate, the light receiving surface opposite the first dielectric layer and the second dielectric layer;
an amorphous silicon layer on the oxide layer; and
an anti-reflective coating (ARC) layer on the amorphous silicon layer, the ARC layer comprising silicon nitride.
21. A solar cell, comprising:
a semiconductor substrate;
a first thin dielectric layer disposed on the semiconductor substrate;
a first semiconductor region of a first conductivity type disposed on the first thin dielectric layer;
a second thin dielectric layer disposed on the semiconductor substrate; and
a second semiconductor region of a second conductivity type disposed on the second thin dielectric layer, the second conductivity type opposite the first conductivity type, wherein the second thin dielectric layer is disposed on a lateral surface of the first semiconductor region, and the second dielectric layer separates the first and second semiconductor regions, wherein the second semiconductor region has a dopant concentration approximately in the range of 1×10 17 -1×10 21 atoms/cm 3 .
22. A solar cell, comprising:
a semiconductor substrate;
a first thin dielectric layer disposed on the semiconductor substrate;
a first semiconductor region of a first conductivity type disposed on the first thin dielectric layer;
a second thin dielectric layer disposed on the semiconductor substrate;
a second semiconductor region of a second conductivity type disposed on the second thin dielectric layer, the second conductivity type opposite the first conductivity type, wherein the second thin dielectric layer is disposed on a lateral surface of the first semiconductor region, and the second dielectric layer separates the first and second semiconductor regions;
an oxide layer disposed over a light receiving surface of the semiconductor substrate, the light receiving surface opposite the first thin dielectric layer and the second thin dielectric layer;
an amorphous silicon layer disposed on the oxide layer; and
an anti-reflective coating (ARC) layer disposed on the amorphous silicon layer, the ARC layer comprising silicon nitride.