Microstructure Evolution During Monocrystalline Silicon Textured in K3PO4 and K2SiO3 Solution

Abstract

The pyramid construction was formed by different K3PO4 concentrations and texturing time. The pyramid microstructure evolution on monocrystalline silicon surface has been studied. We found that the pyramid is approximately 1.3μm in mean size and almost covered the silicon surface with 6wt% K3PO4 for 10min. The pyramid mean size is approximately 1.2 μm and uniform with 26wt% K3PO4 for 5min. Texturing time has a crucial influence on the pyramid size and K3PO4 concentration has a significant influence on the etching rate. With the K3PO4 concentration increasing, the pyramid size becomes smaller, and the etching rate reduces. Furthermore, the average reflectivity of silicon surface has also been studied. For the textured silicon surface, the average reflectivity obtained in the optimal etching conditions (6wt% K3PO4+ 2wt% K2SiO3, 85℃, and 20 min) is close to 11.6%. When texturing time is 5 min, the lowest average reflectivity is about 17.2% with different K3PO4 concentrations. This technique provides an alternative way for production high-efficiency silicon solar cells.