Conductive contacts for polycrystalline silicon features of solar cells
Methods of fabricating conductive contacts for polycrystalline silicon features of solar cells, and the resulting solar cells, are described. In an example, a method of fabricating a solar cell includes providing a substrate having a polycrystalline silicon feature. The method also includes forming a conductive paste directly on the polycrystalline silicon feature. The method also includes firing the conductive paste at a temperature above approximately 700° C. to form a conductive contact for the polycrystalline silicon feature. The method also includes, subsequent to firing the conductive paste, forming an anti-reflective coating (ARC) layer on the polycrystalline silicon feature and the conductive contact. The method also includes forming a conductive structure in an opening through the ARC layer and electrically contacting the conductive contact.
1 . A method of fabricating a solar cell, the method comprising:
forming a substrate having first and second opposing light-receiving surfaces, the first light-receiving surface above the second light-receiving surface;
forming a first tunnel dielectric layer on the first light-receiving surface;
forming a second tunnel dielectric layer on the second light-receiving surface;
forming an N-type polycrystalline silicon layer on the first tunnel dielectric layer;
forming a P-type polycrystalline silicon layer on the second tunnel dielectric layer;
forming a first non-conductive antireflective coating (ARC) layer on the N-type polycrystalline silicon layer;
forming a second non-conductive ARC layer on the P-type polycrystalline silicon layer;
forming a first set of conductive contact structures directly coupled to the N-type polycrystalline silicon layer, a portion of each of the first set of conductive contact structures vertically between the first non-conductive ARC layer and the N-type polycrystalline silicon layer, wherein the portion of each of the first set of conductive contact structures vertically separates the first non-conductive ARC layer from the N-type polycrystalline silicon layer, and wherein an uppermost surface of each of the first set of conductive contact structures is in direct contact with the first non-conductive ARC layer, and wherein a lowermost surface of each of the first set of conductive contact structures is in direct contact with the N-type polycrystalline silicon layer, wherein the lowermost surface of each of the first set of conductive contact structures is opposite the uppermost surface of each of the first set of conductive contact structures, and wherein the lowermost surface of each of the first set of conductive contact structures is parallel with the uppermost surface of each of the first set of conductive contact structures; and
forming a second set of conductive contact structures directly coupled to the P-type polycrystalline silicon layer, a portion of each of the second set of conductive contact structures vertically between the second non-conductive ARC layer and the P-type polycrystalline silicon layer, wherein the portion of each of the second set of conductive contact structures vertically separates the second non-conductive ARC layer from the P-type polycrystalline silicon layer, and wherein a lowermost surface of each of the second set of conductive contact structures is in direct contact with the second non-conductive ARC layer, and wherein an uppermost surface of each of the second set of conductive contact structures is in direct contact with the P-type polycrystalline silicon layer, wherein the uppermost surface of each of the second set of conductive contact structures is opposite the lowermost surface of each of the second set of conductive contact structures, and wherein the uppermost surface of each of the second set of conductive contact structures is parallel with the lowermost surface of each of the second set of conductive contact structures.
2 . The method of claim 1 , wherein the first light-receiving surface is texturized.
3 . The method of claim 2 , wherein the second light-receiving surface is texturized.
4 . The method of claim 1 , wherein a conductive contact of each of the first set of conductive contact structures comprises silver (Ag).
5 . The method of claim 4 , wherein a conductive contact of each of the second set of conductive contact structures comprises silver (Ag).
6 . The method of claim 1 , wherein the first and second non-conductive ARC layers comprise silicon nitride.
7 . The method of claim 1 , wherein the substrate is a monocrystalline silicon substrate.
8 . The method of claim 1 , wherein the first and second tunnel dielectric layers are silicon oxide layers.