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Title: Back-side hydrogenation technique for defect passivation in silicon solar cells

A two-step back-side hydrogenation process includes the steps of first bombarding the back side of the silicon substrate with hydrogen ions with intensities and for a time sufficient to implant enough hydrogen atoms into the silicon substrate to potentially passivate substantially all of the defects and impurities in the silicon substrate, and then illuminating the silicon substrate with electromagnetic radiation to activate the implanted hydrogen, so that it can passivate the defects and impurities in the substrate. The illumination step also annihilates the hydrogen-induced defects. The illumination step is carried out according to a two-stage illumination schedule, the first or low-power stage of which subjects the substrate to electromagnetic radiation that has sufficient intensity to activate the implanted hydrogen, yet not drive the hydrogen from the substrate. The second or high-power illumination stage subjects the substrate to higher intensity electromagnetic radiation, which is sufficient to annihilate the hydrogen-induced defects and sinter/alloy the metal contacts. 3 figures.
Inventors:
Issue Date:
OSTI Identifier:
5131536
Assignee:
Midwest Research Inst., Kansas City, MO (United States) PTO; EDB-94-074260
Patent Number(s):
US 5304509; A
Application Number:
PPN: US 7-934025
Contract Number:
AC02-83CH10093
Resource Relation:
Patent File Date: 24 Aug 1992
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; SILICON; ION IMPLANTATION; SILICON SOLAR CELLS; FABRICATION; CRYSTAL DEFECTS; ELECTROMAGNETIC INTERACTIONS; PHYSICAL RADIATION EFFECTS; REPAIR; BASIC INTERACTIONS; CRYSTAL STRUCTURE; DIRECT ENERGY CONVERTERS; ELEMENTS; EQUIPMENT; INTERACTIONS; PHOTOELECTRIC CELLS; PHOTOVOLTAIC CELLS; RADIATION EFFECTS; SEMIMETALS; SOLAR CELLS; SOLAR EQUIPMENT; 140501* - Solar Energy Conversion- Photovoltaic Conversion; 360605 - Materials- Radiation Effects; 665300 - Interactions Between Beams & Condensed Matter- (1992-)