Insitu epitaxial deposition of front and back junctions in single crystal silicon solar cells

摘要

Fabrication of a single crystal silicon solar cell with an insitu epitaxially deposited very highly doped p-type silicon back surface field obviates the need for the conventional aluminum screen printing step, thus enabling a thinner silicon solar cell because of no aluminum induced bow in the cell. Furthermore, fabrication of a single crystal silicon solar cell with insitu epitaxial p-n junction formation and very highly doped n-type silicon front surface field completely avoids the conventional dopant diffusion step and one screen printing step, thus enabling a cheaper manufacturing process.

主权项

1. A thin epitaxial silicon solar cell comprising:
an epitaxial film of highly doped p-type silicon, said highly doped p-type silicon epitaxial film having a resistivity of less than 10 mohm-cm, said highly doped p-type silicon epitaxial film being a back surface field (BSF) layer; an epitaxial film of p-type silicon on said BSF layer, said p-type silicon epitaxial film being a base layer; an emitter layer at the surface of said base layer; front contacts to said emitter layer on the front surface of said thin epitaxial silicon solar cell; and back contacts to said BSF layer on the back surface of said thin epitaxial silicon solar cell, said back contacts being patterned to cover less than fifty percent of the back surface of said thin epitaxial silicon solar cell; wherein said thin epitaxial silicon solar cell is less than 150 microns thick and wherein said thin epitaxial silicon solar cell is bifacial.