Effect of novel surface treatment on large-area low-cost SOD diffused monocrystalline silicon solar cells

Non-uniformity in the sheet resistance and difficulty in removing the spin glass and other contaminants on wafer surfaces are two major problems confronted after spin-on-doping (SOD). This paper reports a surface treatment process as a possible solution to key problems. The wettability of the silicon surface was enhanced before SOD by maintaining the hydrophilic nature of the surface with a native oxide layer on it, and a novel treatment with hot hydrochloric acid (HCl) was employed as an intermediate step to remove the contaminants easily. Monocrystalline silicon solar cells were fabricated on a large area (103 mm x 103 mm) by using the approach of this study and employing spin-on doping and IR lamp furnace annealing. Uniform sheet resistance, easy removal of surface contaminants after SOD, better performance 'parameters, and low leakage current were the results of the surface treatment approach of this study. Monocrystalline silicon solar cells with conversion efficiencies of 11.9 % and 13.1 % were fabricated on large area monocrystalline silicon wafers with and without a PECVD silicon-nitride antireflection coating.