Metal seed layer for solar cell conductive contact
View Patent ↗Metal seed layers for solar cell conductive contacts and methods of forming metal seed layers for solar cell conductive contacts are described. For example, a solar cell includes a substrate. A semiconductor region is disposed in or above the substrate. A conductive contact is disposed on the semiconductor region and includes a seed layer in contact with the semiconductor region. The seed layer is composed of aluminum (Al) and a second, different, metal.
1. A solar cell, comprising:
a substrate;
a semiconductor region disposed in or above the substrate; and
a conductive contact disposed on the semiconductor region and comprising a seed layer in contact with the semiconductor region, the seed layer comprising aluminum (Al) and a second, different, metal;
wherein the second metal is magnesium (Mg), at least a portion of which is in the form of MgAl 2 O 4 .
2. The solar cell of claim 1 , wherein the second metal has a melting point less than the eutectic melting point of aluminum-silicon (Al—Si).
3. The solar cell of claim 1 , wherein the semiconductor region is a polycrystalline silicon layer of an emitter region disposed above the substrate.
4. The solar cell of claim 1 , wherein the semiconductor region is a diffusion region disposed in the substrate, and wherein the substrate is a monocrystalline silicon substrate.
5. The solar cell of claim 1 , wherein the solar cell is a back-contact solar cell.
6. A back contact solar cell, comprising:
a substrate;
a semiconductor region disposed in or above the substrate;
a conductive contact disposed on the semiconductor region and comprising a seed layer in contact with the semiconductor region, the seed layer comprising aluminum (Al) and a second metal selected from the group consisting of magnesium (Mg), tin (Sn) and zinc (Zn), wherein the Al is in the form of Al/silicon (Al/Si) particles, and wherein the conductive contact further comprises a first metal layer disposed on the seed layer and a second metal layer disposed on the first metal layer;
wherein the seed layer further comprises germanium (Ge).
7. The back contact solar cell of claim 6 , wherein the second metal is a reducing metal.
8. The back contact solar cell of claim 6 , wherein the second metal has a melting point less than the eutectic melting point of aluminum-silicon (Al—Si).