Three-dimensional Macropore Arrays in p-type Silicon Fabricated by Electrochemical Etching

Abstract

Ordered macropores formed in p-type silicon substrates (10 ~ 20 Ω.cm) by using electrochemical anodization in various HF-containing electrolytes was investigated under different operating conditions. The effect of electrolyte composition and etch pits on controlling the formation of macropores on periodically arranged pores is reported. The results revealed that the natures of the constituents of the solution play very important roles in determining pore formation and morphology and that stable ordered macropore growth is not possible without an inverse pyramid notch. By using a Si/SiGe/Si/SiGe/p-type silicon structure, we were able to fabricate ordered pillar structures without an etch pit formation process. A possible role of two sets of Si/SiGe layers in pillar formation is proposed.