Solar cell with silicon oxynitride dielectric layer
View Patent ↗Solar cells with silicon oxynitride dielectric layers and methods of forming silicon oxynitride dielectric layers for solar cell fabrication are described. For example, an emitter region of a solar cell includes a portion of a substrate having a back surface opposite a light receiving surface. A silicon oxynitride (SiO x N y , 0<x, y) dielectric layer is disposed on the back surface of the portion of the substrate. A semiconductor layer is disposed on the silicon oxynitride dielectric layer.
1. An emitter region of a solar cell, the emitter region comprising:
a portion of a substrate having a back surface opposite a front surface;
a silicon oxynitride (SiOxNy, 0<x, y) dielectric layer disposed on the back surface of the portion of the substrate, wherein the silicon oxynitride dielectric layer has a non-homogeneous distribution of nitrogen, wherein the silicon oxynitride dielectric layer has only one nitrogen concentration maxima, wherein a concentration of nitrogen at the maxima is 2-5% and equal to or greater than twice the a nitrogen concentration in another portion of the silicon oxynitride dielectric layer is 0-1%, and wherein the silicon oxynitride dielectric layer is a silicon oxynitride tunnel dielectric layer for the emitter region, wherein the silicon oxynitride dielectric layer has a first surface in contact with the back surface of the portion of the substrate, and a second surface opposite the first surface, and wherein the maxima is at the first surface of the silicon oxynitride dielectric layer; and
a semiconductor layer disposed on the silicon oxynitride dielectric layer.
2. The emitter region of claim 1 , wherein the front surface is a light receiving surface of the solar cell.
3. The emitter region of claim 1 , wherein the silicon oxynitride dielectric layer has a thickness approximately in the range of 10-20 Angstroms.
4. The emitter region of claim 1 , wherein the silicon oxynitride dielectric layer has a composition wherein x>y.
5. The emitter region of claim 1 , wherein the semiconductor layer disposed on the silicon oxynitride dielectric layer is a boron-doped silicon layer, and wherein the silicon oxynitride dielectric layer comprises boron atoms.
6. An emitter region of a solar cell, the emitter region comprising:
a portion of a substrate having a back surface opposite a front surface;
a silicon oxynitride (SiOxNy, 0<x, y) dielectric layer disposed on the back surface of the portion of the substrate, wherein the silicon oxynitride dielectric layer has a non-homogeneous distribution of nitrogen, wherein the silicon oxynitride dielectric layer has only one nitrogen concentration maxima, wherein a concentration of nitrogen at the maxima is 2-5% and equal to or greater than twice the a nitrogen concentration in another portion of the silicon oxynitride dielectric layer is 0-1%, and wherein the silicon oxynitride dielectric layer is a silicon oxynitride tunnel dielectric layer for the emitter region, wherein the silicon oxynitride dielectric layer has a first surface in contact with the back surface of the portion of the substrate, and a second surface opposite the first surface, wherein the maxima is at the first surface of the silicon oxynitride dielectric layer, wherein the silicon oxynitride dielectric layer has a thickness approximately in the range of 10-20 Angstroms, and wherein the silicon oxynitride dielectric layer has a composition wherein x>y; and
a semiconductor layer disposed on the silicon oxynitride dielectric layer.
7. The emitter region of claim 6 , wherein the front surface is a light receiving surface of the solar cell.
8. The emitter region of claim 6 , wherein the semiconductor layer disposed on the silicon oxynitride dielectric layer is a boron-doped silicon layer, and wherein the silicon oxynitride dielectric layer comprises boron atoms.
9. An emitter region of a solar cell, the emitter region comprising:
a portion of a substrate having a back surface opposite a front surface;
a silicon oxynitride (SiOxNy, 0<x, y) dielectric layer disposed on the back surface of the portion of the substrate, wherein the silicon oxynitride dielectric layer has a non-homogeneous distribution of nitrogen, wherein the silicon oxynitride dielectric layer has only one nitrogen concentration maxima, wherein a concentration of nitrogen at the maxima is 2-5% and equal to or greater than twice the a nitrogen concentration in another portion of the silicon oxynitride dielectric layer is 0-1%, and wherein the silicon oxynitride dielectric layer is a silicon oxynitride tunnel dielectric layer for the emitter region, wherein the silicon oxynitride dielectric layer has a first surface in contact with the back surface of the portion of the substrate, and a second surface opposite the first surface, wherein the maxima is at the first surface of the silicon oxynitride dielectric layer, and wherein the silicon oxynitride dielectric layer has a composition wherein x>y; and
a semiconductor layer disposed on the silicon oxynitride dielectric layer, wherein the semiconductor layer disposed on the silicon oxynitride dielectric layer is a boron-doped silicon layer, and wherein the silicon oxynitride dielectric layer comprises boron atoms.
10. The emitter region of claim 9 , wherein the front surface is a light receiving surface of the solar cell.
11. The emitter region of claim 9 , wherein the silicon oxynitride dielectric layer has a thickness approximately in the range of 10-20 Angstroms.