Surface texturing method for silicon solar cell using reactive ion etching with metal mesh

We have developed a new texturing method by forming a pyramidal black silicon structure using a metal mesh in the reactive ion etching (RIE) system in order to overcome the disadvantages of the texturing process using wet etching and the drawbacks of the needle(grass)-like black silicon. For the formation of a pyramidal black silicon on the silicon surface, the RIE system is modified to be equipped with a metal mesh on top of the head shower. The parameters for the RIE process are SF₆/O₂ gas flow of 15/15 sccm, RF (radio frequency) power of 200 W, pressure of 50-200 mTorr, temperature of 5°C, and process time of 5-20 min. An increase in the processing time increases the width of the pyramid; however, the height remains at 0.8 ± 0.1 μm for 15-20 min of processing. The crystalline wafer surface of the pyramidal black silicon of approximately 1.7 ± 0.2 μm width and at 0.8 ± 0.1 μm height in size is textured using the RIE system with 10.7% of reflectivity. Thus, the pyramidal black silicon and the RIE process using a metal mesh are superior to the conventional texturing structures and methods, respectively.