An Electrochemical Cleaning Technique for Removal of Surface Contamination before Texturization of Silicon Solar Cells

In order to decrease the consumption of reagents and silicon during removal of surface contamination before silicon texturing in solar cell manufacturing industry, a new low-cost surface treatment approach of electrochemical cleaning technique （ECT） is reported. In this technique, a powerful oxidizing electrolyte was obtained from the electrochemical reaction on Boron-doped Diamond （BDD） electrodes, and applied during removal of surface contaminations on silicon wafer surfaces. The slightly polished monocrystalline silicon surfaces after cleaning were compared with the ones of primal silicon wafers. The measurement results show that ECT is quite efficient in removing NaCI and organic contaminants. After cleaning, the contrast test was conducted for the textured silicon wafers with/without pre-treatment（polish） separately. The results show that the size of pyramids on the surface without traditional polishing process is homogeneous and smaller than 4 μm, and the average surface reflectance is much lower in the wavelength range from 400 nm to 800 nm. Therefore, the new technique can save silicon material, and effectively avoid optical losses for improving photoconversion effect of solar ceils.