Document Type

Article

Publication Date

2008

Abstract

Silicon substrates exposed to laser ablation in a chemically reactive environment such as SF6 or HCl can experience spontaneous formation of conical pillars. We use these pillars as a template to define the dimensions and order of macropores produced by etching such substrates in aqueous solutions of KOH or tetramethylammonium hydroxide. The pillars anchor the sidewalls of the pores during etching, and the interpillar spacing controls the width of the pores. The macropores have crystallographically defined shapes for which we develop an explanation based on the kinetics of etching. Si(001) macropores can be etched such that they are rectangular with straight walls and an inverted pyramidal bottom. They have been etched as through holes, which is of interest for optical applications. On Si(111), there is a transition from hexagonal to triangular macropores that are all aligned in one direction. The Si(111) pores exhibit an optimum etch time before they begin to disappear. The behavior of the macropores is quite similar regardless of whether the pillars are produced by nanosecond or femtosecond lasers. Differences observed relate to the different initial structures (spacing and regularity) of these two different types of pillar-covered surfaces. (c) 2008 The Electrochemical Society.

Publication Title

Journal of the Electrochemical Society

ISSN

0013-4651

Publisher

Electrochemical Society Inc

Volume

155

Issue

3

DOI

10.1149/1.2826292

Comments

© The Electrochemical Society, Inc. 2008. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS). The archival version of this work was published at http://jes.ecsdl.org/content/155/3/H164.abstract.

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