High efficiency p-type PERC solar cells applying PECVD ALOx layers

Ultrathin (7 nm) ALD Al2O3 layers and high-deposition-rate PECVD AlOx layers have the potential to become the rear surface passivation for the next generation of p-type silicon industrial solar cells. These passivation layers have been applied on laboratory-scale passivated-emitter-and-rear solar cells. Efficiencies higher than 21 % have been achieved. The illuminated current-voltage measurement and the external quantum efficiency confirm that the rear surfaces are providing a high passivation quality and internal reflectance. Based on this experiment we can conclude that these two technologies have probably very similar potential when applied on solar cells. Consequently it will probably be more the deposition system than the deposition technique that will be the main criteria for the choice of one of the technologies. Finaly PECVD and ALD deposition systems are compared in important criteria for industrial solar cell production.