COATED FOIL-BASED METALLIZATION OF SOLAR CELLS
Coated foil-based approaches for metallization of solar cells, and the resulting solar cells, are described. For example, a solar cell includes a substrate. A semiconductor region is disposed in or above the substrate. A conductive contact structure is disposed on and is in electrical contact with the semiconductor region. The conductive contact structure includes a metal foil portion having a first side facing the semiconductor region, and a second side opposite the first side. The second side of the metal foil portion is at least partially coated with an etch-resistant insulating film.
1 . A solar cell, comprising:
a substrate;
a semiconductor region disposed in or above the substrate; and
a conductive contact structure disposed on and in electrical contact with the semiconductor region, the conductive contact structure comprising a metal foil portion having a first side facing the semiconductor region, and a second side opposite the first side, wherein the second side of the metal foil portion is at least partially coated with an etch-resistant insulating film.
2 . The solar cell of claim 1 , wherein the etch-resistant insulating film is a poly(p-xylylene) polymer film.
3 . The solar cell of claim 1 , wherein the etch-resistant insulating film is a fluorocarbon film.
4 . The solar cell of claim 1 , wherein the metal foil portion is joined to the semiconductor region by a welding joint.
5 . The solar cell of claim 1 , wherein the first side of the metal foil portion is at least partially coated with the etch-resistant insulating film.
6 . The solar cell of claim 1 , wherein the etch-resistant insulating film is base-resistant.
7 . The solar cell of claim 1 , wherein the etch-resistant insulating film is acid-resistant.
8 . The solar cell of claim 1 , wherein the metal foil portion is an aluminum foil portion.
9 . The solar cell of claim 8 , wherein the aluminum foil portion is an anodized aluminum foil portion.
10 . The solar cell of claim 1 , wherein the etch-resistant insulating film has a thickness of at least 0.1 micron.
11 . The solar cell of claim 1 , wherein the metal foil portion is adhered to the semiconductor region by a metal seed material.
12 . The solar cell of claim 1 , wherein the semiconductor region is a doped polycrystalline silicon region disposed on a tunneling dielectric layer disposed on the substrate.
13 . The solar cell of claim 1 , wherein the substrate is a monocrystalline silicon substrate, and the semiconductor region is a doped region of the monocrystalline silicon substrate.
14 . A solar cell, comprising:
a substrate;
a semiconductor region disposed in or above the substrate;
a conductive contact structure disposed on and in electrical contact with the semiconductor region, the conductive contact structure comprising a metal foil portion having a first side facing the semiconductor region, and a second side opposite the first side, wherein the second side of the metal foil portion is at least partially coated with an etch-resistant insulating film; and
a welding joint joining the metal foil portion to the semiconductor region, wherein the first side of the metal foil portion is at least partially coated with the etch-resistant insulating film, the etch-resistant insulating film surrounding the welding joint.
15 . The solar cell of claim 14 , wherein the etch-resistant insulating film is a poly(p-xylylene) polymer film.
16 . The solar cell of claim 14 , wherein the etch-resistant insulating film is a fluorocarbon film.
17 . The solar cell of claim 14 , wherein the etch-resistant insulating film is base-resistant or acid-resistant.
18 . A solar cell, comprising:
a substrate;
a semiconductor region disposed in or above the substrate; and
a conductive contact structure disposed on and in electrical contact with the semiconductor region, the conductive contact structure comprising an aluminum foil portion having a first side facing the semiconductor region, and a second side opposite the first side, wherein both the first side and the second side of the aluminum foil portion have a coating thereon, the coating selected from the group consisting of a poly(p-xylylene) polymer film and a fluorocarbon film.
19 . The solar cell of claim 18 , wherein the aluminum foil portion is joined to the semiconductor region by a welding joint, and wherein the coating on the first side of the aluminum foil surrounds the welding joint.
20 . The solar cell of claim 18 , wherein the coating has a thickness of at least 0.1 micron.
21 .- 30 . (canceled)