Abstract: A solar cell is disclosed. The solar cell has a front side facing the sun during normal operation, and a back side facing away from the sun. The solar cell comprises a silicon substrate, a first polysilicon layer with a region of doped polysilicon on the back side of the substrate. The solar cell also comprises a second polysilicon layer with a second region of doped polysilicon on the back side of the silicon substrate. The second polysilicon layer at least partially covers the region of doped polysilicon. The solar cell also comprises a resistive region disposed in the first polysilicon layer. The resistive region extends from an edge of the second region of doped polysilicon. The resistive region can be formed by ion implantation of oxygen into the first polysilicon layer.

Abstract: 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.

Abstract: Methods of fabricating solar cells, and the resulting solar cells, are described herein. In an example, a method of fabricating a solar cell includes forming a thin dielectric layer on a surface of a substrate by radical oxidation or plasma oxidation of the surface of the substrate. The method also involves forming a silicon layer over the thin dielectric layer. The method also involves forming a plurality of emitter regions from the silicon layer.

Abstract: Approaches for the metallization of solar cells and the resulting solar cells are described. In an example, a method of fabricating a solar cell involves forming a plurality of alternating N-type and P-type regions in or above a substrate. The method also involves forming a metal seed layer on the plurality of alternating N-type and P-type regions. The method also involves patterning at least a portion of the metal seed layer at regions in alignment with locations between the alternating N-type and P-type regions. The method also involves, subsequent to the patterning, etching to form trenches at the locations between the alternating N-type and P-type regions, isolating the alternating N-type and P-type regions from one another.

Abstract: A solar cell includes polysilicon P-type and N-type doped regions on a backside of a substrate, such as a silicon wafer. A trench structure separates the P-type doped region from the N-type doped region. Each of the P-type and N-type doped regions may be formed over a thin dielectric layer. The trench structure may include a textured surface for increased solar radiation collection. Among other advantages, the resulting structure increases efficiency by providing isolation between adjacent P-type and N-type doped regions, thereby preventing recombination in a space charge region where the doped regions would have touched.

Abstract: A method of fabricating a solar cell can include forming a dielectric region on a silicon substrate. The method can also include forming an emitter region over the dielectric region and forming a dopant region on a surface of the silicon substrate. In an embodiment, the method can include heating the silicon substrate at a temperature above 900 degrees Celsius to getter impurities to the emitter region and drive dopants from the dopant region to a portion of the silicon substrate.

Abstract: Contact holes of solar cells are formed by laser ablation to accommodate various solar cell designs. Use of a laser to form the contact holes is facilitated by replacing films formed on the diffusion regions with a film that has substantially uniform thickness. Contact holes may be formed to deep diffusion regions to increase the laser ablation process margins. The laser configuration may be tailored to form contact holes through dielectric films of varying thicknesses.

Abstract: A solar cell includes polysilicon P-type and N-type doped regions on a backside of a substrate, such as a silicon wafer. A trench structure separates the P-type doped region from the N-type doped region. Each of the P-type and N-type doped regions may be formed over a thin dielectric layer. The trench structure may include a textured surface for increased solar radiation collection. Among other advantages, the resulting structure increases efficiency by providing isolation between adjacent P-type and N-type doped regions, thereby preventing recombination in a space charge region where the doped regions would have touched.

Abstract: A thin epitaxial silicon solar cell includes one or more layers of doped oxides on the backside. A silicon nitride layer that serves as a moisture barrier is formed on the one or more layers of doped oxides. The doped oxides provide dopants for forming doped regions in an epitaxial silicon layer. Metal contacts are electrically coupled to the doped regions through the silicon nitride layer and the one or more layers of doped oxides.

Abstract: Tri-layer semiconductor stacks for patterning features on solar cells, and the resulting solar cells, are described herein. In an example, a solar cell includes a substrate. A semiconductor structure is disposed above the substrate. The semiconductor structure includes a P-type semiconductor layer disposed directly on a first semiconductor layer. A third semiconductor layer is disposed directly on the P-type semiconductor layer. An outermost edge of the third semiconductor layer is laterally recessed from an outermost edge of the first semiconductor layer by a width. An outermost edge of the P-type semiconductor layer is sloped from the outermost edge of the third semiconductor layer to the outermost edge of the third semiconductor layer. A conductive contact structure is electrically connected to the semiconductor structure.

Abstract: Methods of fabricating solar cell emitter regions with differentiated P-type and N-type regions architectures, and resulting solar cells, are described. In an example, a back contact solar cell can include a substrate having a light-receiving surface and a back surface. A first polycrystalline silicon emitter region of a first conductivity type is disposed on a first thin dielectric layer disposed on the back surface of the substrate. A second polycrystalline silicon emitter region of a second, different, conductivity type is disposed on a second thin dielectric layer disposed on the back surface of the substrate. A third thin dielectric layer is disposed over an exposed outer portion of the first polycrystalline silicon emitter region and is disposed laterally directly between the first and second polycrystalline silicon emitter regions. A first conductive contact structure is disposed on the first polycrystalline silicon emitter region.

Abstract: In one embodiment, harmful solar cell polarization is prevented or minimized by providing a conductive path that bleeds charge from a front side of a solar cell to the bulk of a wafer. The conductive path may include patterned holes in a dielectric passivation layer, a conductive anti-reflective coating, or layers of conductive material formed on the top or bottom surface of an anti-reflective coating, for example. Harmful solar cell polarization may also be prevented by biasing a region of a solar cell module on the front side of the solar cell.

Abstract: Methods of fabricating emitter regions of solar cells are described. Methods of forming layers on substrates of solar cells, and the resulting solar cells, are also described.

Abstract: A method of fabricating a solar cell is disclosed. The method can include forming a dielectric region on a surface of a solar cell structure and forming a metal layer on the dielectric layer. The method can also include configuring a laser beam with a particular shape and directing the laser beam with the particular shape on the metal layer, where the particular shape allows a contact to be formed between the metal layer and the solar cell structure.

Abstract: Methods of fabricating solar cell emitter regions with differentiated P-type and N-type regions architectures, and resulting solar cells, are described. In an example, a back contact solar cell includes a substrate having a light-receiving surface and a back surface. A first polycrystalline silicon emitter region of a first conductivity type is disposed on a first thin dielectric layer disposed on the back surface of the substrate. A second polycrystalline silicon emitter region of a second, different, conductivity type is disposed on a second thin dielectric layer disposed on the back surface of the substrate. A third thin dielectric layer is disposed laterally directly between the first and second polycrystalline silicon emitter regions. A first conductive contact structure is disposed on the first polycrystalline silicon emitter region. A second conductive contact structure is disposed on the second polycrystalline silicon emitter region.

Abstract: Approaches for the foil-based metallization of solar cells and the resulting solar cells are described. In an example, a solar cell includes a substrate. A plurality of alternating N-type and P-type semiconductor regions is disposed in or above the substrate. A conductive contact structure is disposed above the plurality of alternating N-type and P-type semiconductor regions. The conductive contact structure includes a plurality of metal seed material regions providing a metal seed material region disposed on each of the alternating N-type and P-type semiconductor regions. A metal foil is disposed on the plurality of metal seed material regions, the metal foil having anodized portions isolating metal regions of the metal foil corresponding to the alternating N-type and P-type semiconductor regions.

Abstract: Methods of fabricating solar cell emitter regions using ion implantation, and resulting solar cells, are described. In an example, a method of fabricating alternating N-type and P-type emitter regions of a solar cell involves forming a silicon layer above a substrate. Dopant impurity atoms of a first conductivity type are implanted, through a first shadow mask, in the silicon layer to form first implanted regions and resulting in non-implanted regions of the silicon layer. Dopant impurity atoms of a second, opposite, conductivity type are implanted, through a second shadow mask, in portions of the non-implanted regions of the silicon layer to form second implanted regions and resulting in remaining non-implanted regions of the silicon layer. The remaining non-implanted regions of the silicon layer are removed with a selective etch process, while the first and second implanted regions of the silicon layer are annealed to form doped polycrystalline silicon emitter regions.

Abstract: A solar cell is fabricated by etching one or more of its layers without substantially etching another layer of the solar cell. In one embodiment, a copper layer in the solar cell is etched without substantially etching a topmost metallic layer comprising tin. For example, an etchant comprising sulfuric acid and hydrogen peroxide may be employed to etch the copper layer selective to the tin layer. A particular example of the aforementioned etchant is a Co-Bra Etch® etchant modified to comprise about 1% by volume of sulfuric acid, about 4% by volume of phosphoric acid, and about 2% by volume of stabilized hydrogen peroxide. In one embodiment, an aluminum layer in the solar cell is etched without substantially etching the tin layer. For example, an etchant comprising potassium hydroxide may be employed to etch the aluminum layer without substantially etching the tin layer.

Abstract: A solar cell includes polysilicon P-type and N-type doped regions on a backside of a substrate, such as a silicon wafer. A trench structure separates the P-type doped region from the N-type doped region. Each of the P-type and N-type doped regions may be formed over a thin dielectric layer. The trench structure may include a textured surface for increased solar radiation collection. Among other advantages, the resulting structure increases efficiency by providing isolation between adjacent P-type and N-type doped regions, thereby preventing recombination in a space charge region where the doped regions would have touched.

Abstract: A method of fabricating a solar cell is disclosed. The method can include forming a dielectric region on a surface of a solar cell structure and forming a metal layer on the dielectric layer. The method can also include configuring a laser beam with a particular shape and directing the laser beam with the particular shape on the metal layer, where the particular shape allows a contact to be formed between the metal layer and the solar cell structure.