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Nov 28th, 2013
Imec simplifies i-PERC solar cell processing by implementing laser doping from ALD-Al2O3
Nanoelectronics research centre imec announced that they have developed large area (156x156mm2) i-PERC-type silicon solar cells using a new processing sequence based on laser doping from a thin atomic layer deposited (ALD) aluminum oxide (Al2O3) layer to realize the local aluminum Back Surface Field (BSF) and Ni/Cu plating to form the front contact. The cells achieved average conversion efficiencies of 20.2%.
Important step towards reducing cost-of-ownership of PERC technology.
The new laser doping processing sequence eliminates the necessity of a firing step to create the local BSF in i-PERC solar cells. Combined with imec’s Ni/Cu plating sequence for front contact formation, it provides a low temperature metallization solution for i-PERC cells. By avoiding high temperature conditions, passivation degradation of the rear Al2O3 layer, as well as optical degradation of the rear dielectric/metal stack are prevented, resulting in improved solar cell conversion efficiency. Additionally to the performance benefit, this new process sequence is extremely simple because the thin ALD Al2O3 acts at the same time as passivation layer and doping source, while laser processing enables in one step the contact patterning and the local BSF formation.
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