Influence of voltage on photo-electrochemical etching of n-type macroporous silicon arrays

The influence of voltage on photo-electrochemical etching (PEC) of macroporous silicon arrays (MSA) was researched. According to the theory of the space charge region, I?V scan curves and the reaction mechanism of the n-type silicon anodic oxidation in HF solution under different current densities, the pore morphology influenced by the working voltage were studied and analyzed in detail. The results show that increasing the etching voltage will lead to distortion of the pore morphology, decreasing etching voltage will result in an increase in the blind porosity, and the constant etching voltage for a long time will cause gradual bifurcation. Through the optimization of the process parameters, the perfect MSA structure with a pore depth of 317 ?m, a pore size of 3 ?m and an aspect ratio of 105 was obtained.