Laser-annealed, implanted boron emitters for B-BSF silicon solar cells

Boron (B) emitters are required in an increasing number of silicon solar cells technologies, each of them requires an appropriate emitter profile. This work aims at investigating laser thermal annealing (LTA) from implanted B as a versatile approach for B-emitter processing compared to standard furnace annealing. Symmetrical p(+)/n/p(+) structures featuring various LTA B-emitters were characterized using the QssPC technique. Experimental results show that in contrast to thermally-diffused B-emitters, implied V-oc of LTA emitters increases when their sheet resistance decreases. Numerical simulations suggest that the observed trend could be attributed to a reduction in the surface recombination velocity. LTA emitters were then integrated as B-BSF into silicon solar cells. Gains of 2 mV in V-oc and 0.8 mA/cm(2) in J(sc) compared to Al-BSF were obtained, leading to an overall efficiency enhancement of 0.3 %(abs). (C) 2012 Published by Elsevier Ltd. Selection and peer-review under responsibility of the scientific committee of the SiliconPV 2012 conference.