Morphology and growth behavior of P-type Si macropores in submicronmeter prepattern

This paper studies the pore morphology and growth behavior of p-type silicon macropores in submicronmeter prepattern by electrochemistry method. It was found that only random macropores with an average diameter of ~1μm could be formed after electrochemical etching in 3M HF/DMSO solution, while ordered pore arrays are obtained with the assistance of pre-patterning on the Si substrate surface. For micrometer-scale patterns (e.g. 1.6μm), the regular porous structure with high aspect ratio of about 60 is successfully formed after 120 mins of electrochemical etching. However, as the pattern scale reduces to submicronmeter, the capability of pre-patterns in guiding the growth of pores becomes weakened. Regular pore arrays with aspect ratios of 10 and 3 were obtained by etching samples with pre-pattern pitches of 870 nm and 550 nm, respectively.