SiNx Double Layer Antireflection Coating by Plasma-Enhanced Chemical Vapor Deposition for Single Crystalline Silicon Solar Cells

Abstract

Double layer antireflection (DLAR) coatings have significant advantages over single-layer antireflection (SLAR) coatings owing to their coverage of a broad solar spectral range. In this study, the properties of SiNx are examined. DLAR coatings using two thin films of SiNx with different refractive indices are presented. Using the same materials is more cost-effective than using different materials. The total thickness of SiNx/SiNx films is kept at 80 nm. The top SiNx film has a refractive index of 1.9, while the bottom layer has a refractive index of 2.3. Single crystalline solar cells are fabricated with different thicknesses for the top and bottom layers. The solar cell with 60 nm/20 nm SiNx DLAR coatings has 18.3% efficiency, while that with 80 nm SiNx SLAR coating has 17.6% efficiency. The improvement of efficiency is due to the effect of better passivation and better antireflection of DLAR.