Tactical Fabs, Inc.

William T Liggett

Richard L Bechtel

Wen C Ko

Douglas L Peltzer

A point contact solar cell structure and method of manufacturing which provides metal contact from positive and negative bus bars to alternating n-wells and p-wells in a solar cell crystal. The solar cell spans two side-by-side metal bus bars. On the bottom surface of the cell crystal two side-by-side perforated metal layers contact wells of only one conductivity type. Holes in the perforated metal layers are located beneath wells of the opposite conductivity type. An insulated junction between the two perforated metal layers is located directly above the junction between the two side-by-side metal bus bars. Fingers from the perforated metal layer above one bus bar reach across and down to contact the opposite bus bar. Metal lines also reach from the bus bars up through the holes in the perforated contact layers and contact wells within the crystal. This way, all n-wells and p-wells have electrical contact to their respective bus bars. A preferred embodiment includes a passivation layer applied to top and sides of the solar cell after dicing thus providing an anti-reflection coating on the top surface and means for reducing recombination of electrons and holes at edges of the solar crystal back to the interior of the crystal for capture by a p-well or n-well. Benefits include increased cell efficiency, reduced number of masking steps in the manufacturing process as compared to other point contact structures, and improved thermal conductivity through the cell, resulting in lower manufacturing cost and longer cell life.

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Hollister, CA, United States of America

William T Liggett