Research On Metal-assisted Chemical Etching Process Of Silicon Microstructure

Silicon micro-structure is widely used in solar cell, photoelectric device and sensor.Although there are many methods for preparing silicon micro-structure, the metal particles assisted chemical etching is considered to the simplest, most effective and most economical method.In this paper, porous silicon and silicon nanowires were prepared by metal-assisted chemical etching on a silicon substrate. The structure of porous silicon and silicon nanowires of changing the etching time and oxidant concentration was observed. Process of silicon nanowires was optimized, and we analyzed the reasons for the top clusters of silicon nanowires. Pores of porous silicon become large and uneven with the etching time increases,when the oxidant concentration is 0.5mol/L and the etching time is 15 min, the pore size become uniform and better morphology. The porosity with etching time is first increase, then the change trend of decreases. The reflectivity is inversely proportional to etching time. The length of silicon nanowires becomes longer with the increase of etching time and oxidant concentration. After optimizing the process, the phenomenon of collapse of silicon nanowires effectively is avoided. Due to the interaction of three forces, Van der Waals Force,Surface Tension, Elastic Deformation Force, silicon nanowires produce the top clusters.