Method For Low Temperature Plasma Enhanced Chemical Vapor Deposition (pecvd) Of An Oxide And Nitride Antireflection Coating On Silicon

Abstract

A sequential plasma-enhanced chemical vapor deposition (PECVD) of SiN and SiOx produces a very effective double-layer antireflection coating. This antireflection coating is compared with the frequently used and highly efficient double-layer MgF₂ /ZnS coating. It is shown that the double-layer SiOx /SiN coating improves the short-circuited current (Jsc) by 47%, open-circuit voltage (Voc) by 3.7%, and efficiency (Eff) by 55% for silicon cells with oxide surface passivation. The counterpart MgF₂ /ZnS coating gives smaller improvement in Voc and Eff. However, if silicon cells do not have the oxide passivation, the PECVD SiOx /SiN gives much greater improvement in the cell parameters, 57% in Jsc, 8% in Voc, and 66% in efficiency, compared to the MgF₂ /ZnS coating which improves Jsc by 50%, Voc by 2%, and cell efficiency by 54%. This significant additional improvement results from the PECVD deposition-induced surface/defect passivation. The internal quantum efficiency (IQE) measurements showed that the PECVD SiOx /SiN coating absorbs fair amount of photons in the short-wavelength range ( <500 nm), however, the improved surface/defect passivation more than compensates for the loss in Jsc and gives higher improvement in the cell efficiency compared to the MgF i/ZnS coating.