Laser‐fired contact for n‐type crystalline Si solar cells

Abstract

Abstract Laser‐fired contacts to n‐type crystalline silicon were developed by investigating novel metal stacks containing Antimony (Sb). Lasing conditions and the structure of metals stacks were optimized for lowest contact resistance and minimum surface damage. Specific contact resistance for firing different metal stacks through either silicon nitride or p‐type amorphous silicon was determined using two different models and test structures. Specific contact resistance values of 2–7 mΩcm 2 have been achieved. Recombination loss due to laser damage was consistent with an extracted local surface recombination velocity of ~20 000 cm/s, which is similar to values for laser‐fired base contact for p‐type crystalline silicon. Interdigitated back contact silicon heterojunction cells were fabricated with laser‐fired base contact and proof‐of‐concept efficiencies of 16.9% were achieved. This localized base contact technique will enable low cost back contact patterning and innovative designs for n‐type crystalline solar cell. Copyright © 2014 John Wiley & Sons, Ltd.