Shielded electrical contact and doping through a passivating dielectric layer in a high-efficiency crystalline solar cell, including structure and methods of manufacture

摘要

Solar cell structures and formation methods which utilize the surface texture in conjunction with a passivating dielectric layer to provide a practical and controllable technique of forming an electrical contact between a conducting layer and underlying substrate through the passivating dielectric layer, achieving both good surface passivation and electrical contact with low recombination losses, as required for high efficiency solar cells. The passivating dielectric layer is intentionally modified to allow direct contact, or tunnel barrier contact, with the substrate. Additional P-N junctions, and dopant gradients, are disclosed to further limit losses and increase efficiency.

主权项

1. A method comprising:
providing a textured substrate the textured substrate comprising geometrical texture structures having shapes comprising upper peaks; providing a passivating dielectric layer over the textured substrate; and preferentially etching the passivating layer over the upper peaks of the geometrical texture structures to form controlled contact openings through the passivating dielectric layer to the upper peaks, the preferentially etching comprising introducing, during the preferential etching, an electrical bias into the substrate, the electrical bias producing an increased electric field strength at the upper peaks, the increased electric field strength facilitating the preferential etching of the passivating dielectric layer from over the user peaks of the geometrical texture structures.