Simplified PERC solar cells passivated with PECVD silicon nitride

Abstract

Stoichiometric plasma enhanced chemical vapor deposited silicon nitride films have been used to passivate the front and rear surface of simplified PERC silicon solar cells. These films have the distinctive properties that they can provide excellent surface passivation, are easily patterned using photolithography and wet chemical etching, and are compatible with aluminium layers for a back surface optical reflector. Cells with planar surfaces and random pyramid texturing have been fabricated. Open circuit voltages up to 667mV have been measured on float-zone substrates and 655mV on multicrystalline material, proving the outstanding surface passivation provided by the silicon nitride films. Conversion efficiencies of 18.5% and 16.1% have been obtained respectively.