Reactive Ion Etching Texturing for Multicrystalline Silicon Solar Cells Using a SF6/O2/Cl2 Gas Mixture

Maskless random reactive ion etching (RIE) texturing employing a SF6/O-2/Cl-2 gas mixture was investigated in order to achieve higher efficiencies in multicrystalline silicon (mc-Si) solar cells. Triangular pyramid structures with an aspect ratio of 1 were formed and, when the RIE power increased, the average reflectance was reduced by about 1.46% per 10 W. This was due to the increased density of the surface features. The performances of all of the RIE-textured mc-Si solar cells were improved compared with that of the reference cell. Among them, the 110 W cell, which had a 0.6% higher efficiency than the reference cell, had the highest efficiency of 16.82%. An impedance analysis was carried out to determine series resistance (R-s), shunt resistance (R-sh), and junction capacitance (C-j). Interestingly, the cell with higher efficiencies and higher structure densities had higher linear reverse currents. (c) 2013 The Japan Society of Applied Physics