Solar cell with reduced base diffusion area
AssigneeSunPower Corporation
InventorsDenis De Ceuster, Peter John Cousins
Life of this patent
Estimating the term…
Abstract
In one embodiment, a solar cell has base and emitter diffusion regions formed on the back side. The emitter diffusion region is configured to collect minority charge carriers in the solar cell, while the base diffusion region is configured to collect majority charge carriers. The emitter diffusion region may be a continuous region separating the base diffusion regions. Each of the base diffusion regions may have a reduced area to decrease minority charge carrier recombination losses without substantially increasing series resistance losses due to lateral flow of majority charge carriers. Each of the base diffusion regions may have a dot shape, for example.
Claims20
A solar cell comprising:
- a continuous emitter diffusion region for collecting minority charge carriers in a solar cell, the continuous emitter diffusion region being formed on a back side of the solar cell;
- a plurality of dotted base diffusion regions for collecting majority charge carriers in the solar cell, the plurality of dotted base diffusion regions being surrounded by the continuous emitter diffusion region on the back side of the solar cell;
- a first metal grid electrically coupled to at least two dotted base diffusion regions in the plurality of dotted base diffusion regions;
- a first insulator layer between the first metal grid and the at least two dotted base diffusion regions, the first metal grid being electrically coupled to the at least two dotted base diffusion regions through at least two contact holes that go through the first insulator layer;
- and
- a second metal grid electrically coupled to the continuous emitter diffusion region, wherein the first and second metal grids are formed on the back side of the solar cell.
A method of fabricating a solar cell, the method comprising:
- forming a first doped layer over a first surface of a substrate, the first doped layer including a plurality of openings through which portions of the substrate are exposed;
- forming a second doped layer at least in the plurality of openings in the first doped layer;
- diffusing a first dopant from the first doped layer to form a continuous emitter diffusion region on a back side of the solar cell, the emitter diffusion region being configured to collect minority charge carriers in the solar cell;
- diffusing a second dopant from the second doped layer formed in the plurality of openings to form a plurality of base diffusion regions on the back side of the solar cell, the plurality of base diffusion regions being configured to collect majority charge carriers in the solar cell;
- forming a first metal grid on the back side of the solar cell, the first metal grid being electrically coupled to the emitter diffusion region;
- and
- forming a second metal grid on the back side of the solar cell, the second metal grid being electrically coupled to a base diffusion region in the plurality of base diffusion regions.
A solar cell comprising:
- a plurality of base diffusion regions configured to collect majority charge carriers on a back side of a solar cell;
- a continuous emitter diffusion region configured to collect minority charge carriers on the back side of the solar cell, the continuous emitter diffusion region surrounding each base diffusion region in the plurality of base diffusion regions;
- a first metal grid electrically coupled to at least one base diffusion region in the plurality of base diffusion regions;
- and
- a second metal grid electrically coupled to the continuous emitter diffusion region.
Dependencies are inferred from the claim text.