Thermally stable A-Si:H/SiNx stack passivating system and the application on rear-localized contact solar cells on CZ p-type crystalline silicon

For the purpose of manufacturing high efficiency crystalline silicon solar cells with a passivated rear surface and local contacts, a thermally stable passivating system of plasma-enhanced chemical vapor deposition (PECVD) deposited a-Si:H/SiNx:H stack was developed in this work. Effective lifetime (τ_eff) of 1.08ms and 1.7ms were demonstrated on 4.5ohm.cm CZ silicon wafers and 1ohm.cm FZ wafers respectively with this stack passivating system. Corresponding Surface recombination velocity (SRV) of 5.8cm/s was calculated for the FZ wafer. Good thermal stability capable of withstanding over 90min thermal annealing at 400°C suggested the compatibility of this stack passivating system to the metal contacting schemes that require relatively low sintering temperatures. Cell efficiency of up to 19.32% on a 5.29cm² industrial B-doped CZ silicon wafer was achieved with this stack passivating system.