Solar cell emitter region fabrication using silicon nano-particles

A method of fabricating an emitter region of a solar cell, the method comprising:

• forming a region of doped nano-particles above a dielectric layer disposed above a back surface of a substrate of the solar cell, the back surface opposite a light-receiving surface of the solar cell;
• forming a layer of silicon on both the light-receiving surface and above the back surface of the substrate, including a portion on the region of doped nano-particles and a portion on the dielectric layer;
• mixing the portion of the layer of silicon formed on the region of doped nano-particles with at least a portion of the region of doped nano-particles to form a doped polycrystalline silicon layer disposed on the dielectric layer;
• oxidizing the layer of silicon on the light-receiving surface of the substrate, the portion of the layer of silicon on the dielectric layer, and an outermost region of the doped polycrystalline silicon layer to form a silicon oxide layer on the light receiving surface and above the back surface of the substrate;
• and forming an anti-reflective coating layer on the silicon oxide layer on the light receiving surface and on the silicon oxide layer above the back surface of the substrate.

A method of fabricating an emitter region of a solar cell, the method comprising:

• forming a region of N-Type doped nano-particles and a region of P-type doped nano-particles above a dielectric layer disposed above a back surface of a substrate of the solar cell, the back surface opposite a light-receiving surface of the solar cell, and the region of N-Type doped nano-particles adjacent to but not in contact with the region of P-type doped nano-particles;
• forming a layer of silicon at least above the back surface of the substrate, including a portion on the regions of N-type and P-type doped nano-particles and a portion on the dielectric layer;
• mixing the portion of the layer of silicon formed on the regions of N-type and P-type doped nano-particles with at least a portion of each of the regions of N-type and P-type doped nano-particles to form an N-type doped polycrystalline silicon layer and a P-type doped polycrystalline silicon layer, respectively, each disposed on the dielectric layer;
• oxidizing the portion of the layer of silicon on the dielectric layer, and an outermost region of the each of the N-type and P-type doped polycrystalline silicon layers to form a silicon oxide layer above the back surface of the substrate;
• masking and etching the silicon oxide layer above the back surface of the substrate to provide an N-type doped polysilicon region and a P-type doped polycrystalline silicon region separated by a trench formed in the back surface of the substrate, each of the N-type doped polysilicon region and the P-type doped polycrystalline silicon region retaining a portion of the silicon oxide layer thereon;
• and
• forming an anti-reflective coating layer on the N-type doped polysilicon region and the P-type doped polycrystalline silicon region and in the trench.