Sunpower Corporation

Tetrasun, Inc.

Denis De Ceuster

David D Smith

Richard M Swanson

Peter John Cousins

Douglas H Rose

Neil Kaminar

Vikas Desai

Jane Manning

Hsin-Chiao Luan

Peter Cousins

Douglas E Crafts

Oliver Schultz-Wittmann

Adrian Bruce Turner

Peter J Cousins

Jane E Manning

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.

Solar cell with reduced base diffusion area

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.

Preventing harmful polarization of solar cells

A multilayer anti-reflection structure for a backside contact solar cell. The anti-reflection structure may be formed on a front side of the backside contact solar cell. The anti-reflection structure may include a passivation level, a high optical absorption layer over the passivation level, and a low optical absorption layer over the high optical absorption layer. The passivation level may include silicon dioxide thermally grown on a textured surface of the solar cell substrate, which may be an N-type silicon substrate. The high optical absorption layer may be configured to block at least 10% of UV radiation coming into the substrate. The high optical absorption layer may comprise high-k silicon nitride and the low optical absorption layer may comprise low-k silicon nitride.

Anti-reflective coating with high optical absorption layer for backside contact solar cells

A solar cell formation method, and resulting structure, having a first film and a barrier film over a surface of a doped semiconductor, wherein the optical and/or electrical properties of the first film are transformed in-situ such that a resulting transformed film is better suited to the efficient functioning of the solar cell; wherein portions of the barrier film partially cover the first film and substantially prevent transformation of first film areas beneath the portions of the barrier film.

Selective transformation in functional films, and solar cell applications thereof

A solar cell includes polysilicon P-type and N-type doped regions on a backside of a substrate, such as a silicon wafer. An interrupted trench structure separates the P-type doped region from the N-type doped region in some locations but allows the P-type doped region and the N-type doped region to touch in other locations. Each of the P-type and N-type doped regions may be formed over a thin dielectric layer. Among other advantages, the resulting solar cell structure allows for increased efficiency while having a relatively low reverse breakdown voltage.

Trench process and structure for backside contact solar cells with polysilicon doped regions

In one embodiment, active diffusion junctions of a solar cell are formed by diffusing dopants from dopant sources selectively deposited on the back side of a wafer. The dopant sources may be selectively deposited using a printing method, for example. Multiple dopant sources may be employed to form active diffusion regions of varying doping levels. For example, three or four active diffusion regions may be fabricated to optimize the silicon/dielectric, silicon/metal, or both interfaces of a solar cell. The front side of the wafer may be textured prior to forming the dopant sources using a texturing process that minimizes removal of wafer material. Openings to allow metal gridlines to be connected to the active diffusion junctions may be formed using a self-aligned contact opening etch process to minimize the effects of misalignments.

Back side contact solar cell structures and fabrication processes

A multilayer anti-reflection structure for a backside contact solar cell. The anti-reflection structure may be formed on a front side of the backside contact solar cell. The anti-reflection structure may include a passivation level, a high optical absorption layer over the passivation level, and a low optical absorption layer over the high optical absorption layer. The passivation level may include silicon dioxide thermally-grown on a textured surface of the solar cell substrate, which may be an N-type silicon substrate. The high optical absorption layer may be configured to block at least 10% of UV radiation coming into the substrate. The high optical absorption layer may comprise high-k silicon nitride and the low optical absorption layer may comprise low-k silicon nitride.

Growing community of inventors

Woodside, CA, United States of America

Denis De Ceuster