Solar cells having differentiated P-type and N-type architectures
Methods of fabricating solar cell emitter regions with differentiated P-type and N-type region architectures, and the resulting solar cells, are described herein. In an example, a solar cell includes an N-type semiconductor substrate having a light-receiving surface and a back surface. A plurality of N-type polycrystalline silicon regions is disposed on a first thin dielectric layer disposed on the back surface of the N-type semiconductor substrate. A plurality of P-type polycrystalline silicon regions is disposed on a second thin dielectric layer disposed in a corresponding one of a plurality of trenches interleaving the plurality of N-type polycrystalline silicon regions in the back surface of the N-type semiconductor substrate.
1. A solar cell, comprising:
an N-type substrate having a light-receiving surface and a back surface;
a first dielectric layer disposed on the back surface of the substrate;
an N-type polycrystalline silicon emitter region disposed on the first dielectric layer;
a P-type polycrystalline silicon emitter region disposed on a second dielectric layer, wherein a total area of the N-type polycrystalline silicon emitter region is greater than a total area of the P-type polycrystalline silicon emitter region by a ratio of 15:1 or more;
a third dielectric layer disposed laterally directly between the N-type and P-type polycrystalline silicon emitter regions;
a first conductive contact structure disposed on the N-type polycrystalline silicon emitter region; and
a second conductive contact structure disposed on the P-type polycrystalline silicon emitter region, wherein the P-type polycrystalline silicon emitter region overlaps the N-type polycrystalline silicon emitter region.
2. The solar cell of claim 1 , wherein the N-type polycrystalline silicon emitter region has a width greater than a width of each of the P-type polycrystalline silicon emitter region by a ratio of 5:1 or more.
3. The solar cell of claim 1 , wherein the N-type polycrystalline silicon emitter region has a thickness relative to a thickness of the P-type polycrystalline silicon emitter region by a ratio of 3:1 or less.
4. A solar cell, comprising:
an N-type substrate having a light-receiving surface and a back surface;
a first dielectric layer disposed on the back surface of the substrate;
an N-type polycrystalline silicon emitter region of a first conductivity type disposed on the first dielectric layer;
a second dielectric layer disposed on the back surface of the substrate;
a P-type polycrystalline silicon emitter region disposed on the second dielectric layer, wherein a total area of the N-type polycrystalline silicon emitter region is greater than a total area of the P-type polycrystalline silicon emitter region by a ratio of 15:1 or more;
a third dielectric layer disposed directly between the N-type polycrystalline silicon emitter region and the P-type polycrystalline silicon emitter region;
an insulator layer disposed on the N-type polycrystalline silicon emitter region, wherein at least a portion of the P-type polycrystalline silicon emitter region is disposed on the insulator layer;
a first conductive contact structure disposed on the N-type polycrystalline silicon emitter region; and
a second conductive contact structure disposed on the P-type polycrystalline silicon emitter region, wherein the P-type polycrystalline silicon emitter region overlaps the N-type polycrystalline silicon emitter region.
5. The solar cell of claim 4 , wherein the N-type polycrystalline silicon emitter region has a width greater than a width of the P-type polycrystalline silicon emitter region by a ratio of 5:1 or more.
6. The solar cell of claim 4 , wherein the plurality of N-type polycrystalline silicon emitter region has a thickness relative to a thickness of the P-type polycrystalline silicon emitter region by a ratio of 3:1 or less.
7. A solar cell, comprising:
an N-type substrate having a light-receiving surface and a back surface;
a first dielectric layer disposed on the back surface of the substrate;
an N-type polycrystalline silicon emitter region disposed on the first dielectric layer;
a P-type polycrystalline silicon emitter region disposed on a second dielectric layer, wherein a total area of the N-type polycrystalline silicon emitter region is greater than a total area of the P-type polycrystalline silicon emitter region, and wherein the N-type polycrystalline silicon emitter region has a width greater than a width of each of the P-type polycrystalline silicon emitter region by a ratio of 5:1 or more;
a third dielectric layer disposed laterally directly between the N-type and P-type polycrystalline silicon emitter regions;
a first conductive contact structure disposed on the N-type polycrystalline silicon emitter region; and
a second conductive contact structure disposed on the P-type polycrystalline silicon emitter region, wherein the P-type polycrystalline silicon emitter region overlaps the N-type polycrystalline silicon emitter region.
8. The solar cell of claim 7 , wherein the N-type polycrystalline silicon emitter region has a thickness relative to a thickness of the P-type polycrystalline silicon emitter region by a ratio of 3:1 or less.
9. The solar cell of claim 7 , wherein the first dielectric layer comprises silicon and oxygen.
10. The solar cell of claim 7 , wherein the second dielectric layer comprises silicon and oxygen.
11. A solar cell, comprising:
an N-type substrate having a light-receiving surface and a back surface;
a first dielectric layer disposed on the back surface of the substrate;
an N-type polycrystalline silicon emitter region of a first conductivity type disposed on the first dielectric layer;
a second dielectric layer disposed on the back surface of the substrate;
a P-type polycrystalline silicon emitter region disposed on the second dielectric layer, wherein a total area of the N-type polycrystalline silicon emitter region is greater than a total area of the P-type polycrystalline silicon emitter region, and wherein the N-type polycrystalline silicon emitter region has a width greater than a width of the P-type polycrystalline silicon emitter region by a ratio of 5:1 or more;
a third dielectric layer disposed directly between the N-type polycrystalline silicon emitter region and the P-type polycrystalline silicon emitter region;
an insulator layer disposed on the N-type polycrystalline silicon emitter region, wherein at least a portion of the P-type polycrystalline silicon emitter region is disposed on the insulator layer;
a first conductive contact structure disposed on the N-type polycrystalline silicon emitter region; and
a second conductive contact structure disposed on the P-type polycrystalline silicon emitter region, wherein the P-type polycrystalline silicon emitter region overlaps the N-type polycrystalline silicon emitter region.
12. The solar cell of claim 11 , wherein the plurality of N-type polycrystalline silicon emitter region has a thickness relative to a thickness of the P-type polycrystalline silicon emitter region by a ratio of 3:1 or less.
13. The solar cell of claim 11 , wherein the first dielectric layer comprises silicon and oxygen.
14. The solar cell of claim 11 , wherein the second dielectric layer comprises silicon and oxygen.
15. The solar cell of claim 1 , wherein the N-type polycrystalline silicon emitter region has a width greater than a width of each of the P-type polycrystalline silicon emitter region by a ratio of 5:1 or more, and wherein the N-type polycrystalline silicon emitter region has a thickness relative to a thickness of the P-type polycrystalline silicon emitter region by a ratio of 3:1 or less.
16. The solar cell of claim 1 , wherein the first dielectric layer comprises silicon and oxygen.
17. The solar cell of claim 1 , wherein the second dielectric layer comprises silicon and oxygen.
18. The solar cell of claim 4 , wherein the N-type polycrystalline silicon emitter region has a width greater than a width of the P-type polycrystalline silicon emitter region by a ratio of 5:1 or more, and wherein the plurality of N-type polycrystalline silicon emitter region has a thickness relative to a thickness of the P-type polycrystalline silicon emitter region by a ratio of 3:1 or less.
19. The solar cell of claim 4 , wherein the first dielectric layer comprises silicon and oxygen.
20. The solar cell of claim 4 , wherein the second dielectric layer comprises silicon and oxygen.