High-Quality Surface Passivation Obtained by High-Rate Deposited Silicon Nitride, Silicon Dioxide and Amorphous Silicon using the Versatile Expanding Thermal Plasma Technique

Abstract

The expanding thermal plasma (ETP) is a novel plasma technique currently used by several solar cell manufacturers for the deposition of silicon nitride antireflection coatings on (multi-) crystalline silicon solar cells. In this paper we will show that the ETP technique is versatile and can be used for the deposition of silicon nitride, silicon dioxide and hydrogenated amorphous silicon with a good level of surface passivation. In this way the ETP technique can meet the future PV demands with respect to the decrease in wafer thickness and the use of n-type material that requires good electrical and optical quality thin films at both the front and the back side of the solar cell.

Surface passivation of crystalline silicon by amorphous silicon carbide films for photovoltaic applications

“…Developing amorphous silicon at relatively higher temperatures could lead in principle to more stable films under post annealing effects. This was tried, for example, by means of the Expanding Plasma Technique, in which amorphous silicon grown at 400 ºC led to excellent surface passivation in 1.9 Ω cm n-type silicon, achieving S eff between 7 and 15 cm s -1 at interesting deposition rates higher than 1 nm s -1 [112]. After a FGA treatment at 400 ºC the effective recombination velocity increases significantly at about 60 cm s -1 , which is a value significantly higher but that can be still considered in the level of good surface passivation.…”