Study on Surface Texturization of Monocrystalline Silicon Wafers with Na2CO3 and NaHCO3 Solutions

The surface texturization of monocrystalline silicon wafers based on a mixture of sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3) solutions under different conditions have been studied in this work. A series of comparative experiments were made to indicate the dependence of hemispherical surface reflectivity on the Na2CO3 concentration, the NaHCO3 concentration and the solution temperature. The results showed that the Na2CO3 concentration and the solution temperature have great effects on texture. In addition, the pyramid size and the surface average reflectivity decreased with the addition of NaHCO3. On the basis of our experiments, it is shown that the optimized conditions are 24 wt% Na2CO3, 4 wt% NaHCO3, 90 °C and 30 min. Under these conditions, uniform pyramids are fabricated and the textured silicon surface exhibits a lower average reflectivity (about 12.34%) in the main range of solar spectrum (400 nm-800 nm). Because this texturization method is economical, nonhazardous and has low pollution, so we feel that it is an attractive alternative for the industrial production.