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Interdigitated back contact silicon solar cells fabrication using diffusion barriers

  • US 9,054,237 B2
  • Filed: 11/24/2010
  • Issued: 06/09/2015
  • Est. Priority Date: 09/09/2008
  • Status: Active Grant
First Claim
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1. A method of fabricating an interdigitated back contact solar cell, the method comprising:

  • diffusing a first dopant into first and second substrate regions through a planar rear surface of a semiconductor substrate such that the first dopant forms first and second spaced-apart diffusion regions in said first and second substrate regions having a first doping concentration and extending a first depth into the substrate from the planar rear surface, and are separated by a third substrate region having a second doping concentration and extending a second depth into the substrate from the planar rear surface, wherein diffusing the first dopant includes;

    depositing spaced-apart pads of material containing boron onto the planar rear surface of substrate over said first and second substrate regions; and

    heating the substrate such that a first portion of the boron diffuses into said first and second substrate regions through said planar rear surface to form said first and second diffusion regions, and such that a second portion of the boron forms spaced-apart first and second borosilicate glass structures on said planar rear surface over said first and second diffusion regions; and

    after forming said spaced-apart first and second borosilicate glass structures, diffusing a second dopant into said third substrate region through said planar rear surface of said semiconductor substrate such that said second dopant passes between said spaced-apart first and second borosilicate glass structures and forms a third diffusion region in said third substrate region, and such that said second dopant disposed in the third diffusion region forms a first interface with the first dopant disposed in the first diffusion region and a second interface with the first dopant disposed in the second diffusion region, wherein said first and second spaced-apart borosilicate glass structures form effective barriers that prevent diffusion of said second dopant into said first and second substrate regions during said diffusing of said second dopant.

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