Excellent thermal stability of remote plasma-enhanced chemical vapour deposited silicon nitride films for the rear of screen-printed bifacial silicon solar cells

In this work the thermal stability of the electronic surface passivation of remote plasma-enhanced chemical vapour deposited (RPECVD) silicon nitride (SiN) films is investigated with the aim to establish a cost-effective screen-printing and firing-through-the-SiN process for bifacial silicon (Si) solar cells. As a key result, RPECVD SiN films provide an excellently thermally stable surface passivation quality if they feature a refractive index in the range between 2.0 and 2.2. After a short anneal above 850°C the surface recombination velocity on 1.5 Ωcm p-type float-zone (FZ) Si remains at a very low level of about 20 cm/s. First bifacial silicon solar cells with screen-printed rear contacts on 1.5 Ωcm p-type FZ Si yield a very promising rear efficiency of 13.4%.