High-rate silicon nitride deposition for photovoltaics : from fundamentals to industrial application

The development of a novel plasma technique for high rate (> 1 nm/s) silicon nitride deposition for multifunctional antireflection coatings on crystalline silicon solar cells is described. The research has involved the analysis of the structural and optical properties of the silicon nitride films as obtained under different operating conditions using the N2-SiH4 and NH3-SiH4 reactant mixture. Furthermore, the fundamental plasma processes and the film growth mechanism have been studied in terms of plasma chemistry, plasma species, and their contribution to film growth. The feasibility of the application of the high-rate deposited silicon nitride as a bulk passivating antireflection coating has been proven by lab-scale experiments on multicrystalline silicon solar cells and the successful transfer of the technique into an industrial inline deposition system for high-volume production of solar cells is reported.