Formation of high aspect ratio macropore array on p-type silicon

Abstract

The fabrication of high aspect ratio macropore arrays on p-type silicon under optimum anodization conditions is demonstrated. The depth of the macropore can reach 400 μm with an aspect ratio of 100. The thickness of the pore wall is 1-2 μm. Presence of cationic surfactant in the electrolyte protects the pore walls and promotes the growth of the unidirectional macropores. The shape of preetched pits is critical for the formation of high aspect ratio macropores on p-type silicon. A self-supported silicon membrane of straight-through macroporous channels has also been obtained.