Fabrication of Silicon-based Micro Pore Array with Large-area and High Aspect-ratio by Photo-electrochemical Etching

The micro pore array with the feature of aspect ratio of more than 50 was fabricated on a 5-inch silicon wafer by means of photo-assisted electrochemical etching technique.After analyzing the factors that determine the morphology of pores,the following experiments were proceeded to study the relation of pore morphology to the etching voltage and electric current.When choosing a current by i-V curve,several different etching voltages were applied respectively and corresponding wafer was fabricated by adjusting experimental parameters according to the Lehmann′s model.It was found that the better pores could be produced under a voltage of 2 V.The results show that photo-assisted electrochemical etching technique can be more adopted to make the large area micro-pore array of high aspect-ratio on silicon wafer with low cost,being compared to the state of the art of micro-manufacturing technology.