Contact fabrication of emitter wrap-through back contact silicon solar cells
AssigneeApplied Materials, Inc.
InventorsPeter HACKE, James M. Gee
Life of this patent
Estimating the term…
Abstract
Back contact solar cells including rear surface structures and methods for making same. The rear surface has small contact areas through at least one dielectric layer, including but not limited to a passivation layer, a nitride layer, a diffusion barrier, and/or a metallization barrier. The dielectric layer is preferably screen printed. Large grid areas overlay the dielectric layer. The methods provide for increasing efficiency by minimizing p-type contact areas and maximizing n-type doped regions on the rear surface of a p-type substrate.
Claims20
A method of forming a solar cell, comprising:
- depositing a patterned diffusion barrier on a rear surface of a substrate, the substrate having a first conductivity type;
- forming a diffusion zone on a front surface of the substrate and on regions of the rear surface not covered by the diffusion barrier, wherein the diffusion zone has a second conductivity type opposite to that of the first conductivity type;
- disposing a first conductive grid on the diffusion barrier in electrical contact with the substrate in a subset of the regions of the rear surface not covered by the diffusion barrier;
- and
- disposing a second conductive grid on the rear surface in electrical contact with the diffusion zone.
A method of forming a solar cell, comprising:
- depositing a patterned diffusion barrier on a rear surface of a substrate, the substrate having a first conductivity type;
- forming a diffusion zone comprising an opposite conductivity type on regions of the rear surface not covered by the diffusion barrier and a front surface of the substrate, wherein the diffusion zone has a second conductivity type opposite to that of the first conductivity type;
- depositing a metallization barrier on the rear surface, the metallization barrier comprising:
- first openings smaller than the first regions;
- and
- second openings aligned with and smaller than second regions of the rear surface that had been covered by the diffusion barrier;
- disposing a first conductive grid partially on the metallization barrier and in electrical contact with the diffusion through the first openings;
- and
- disposing a second conductive grid partially on the metallization barrier and in electrical contact with the substrate through the second openings.
Dependencies are inferred from the claim text.