Macropore Formation in p-type Silicon and Si/SiGe/Si/SiGe/p-type Silicon

Abstract

Random and ordered macropore formation in p-type silicon substrate (10 ~ 20 ohm•cm) by electrochemical anodization in various HF-containing electrolytes was investigated under different operating conditions. The effect of electrolyte composition controlling the macropore formation both for random and periodically arranged pores is reported. The role played by etch pit for ordered macropore formation was investigated. The results revealed that the nature of constituents of solution plays very important roles in determining pore formation and morphology and the stable ordered macropore growth is not possible without etch pit. By using Si/SiGe/Si/SiGe/p-type silicon structure, ordered pillar structures were fabricated without etch pit formation process. The possible role of two sets of Si/SiGe layer for pillar formation is proposed.