Characterization of low-temperature bulk micromachining of silicon using an SF6/O2 inductively coupled plasma

Jiang, F
Keating, A
Martyniuk, M
Prasad, K
Faraone, L
Dell, JM
Item type
Journal Article
Degree name
Journal Title
Journal ISSN
Volume Title
IOP Publishing

The principal aim of this work was to characterize deep silicon etching at sample temperatures well-below room temperature, using SF6/O2 inductively coupled plasma (ICP) for micro-electro-mechanical systems (MEMS) applications. In this paper, a study of the etch rates and etch profiles of deep silicon trenches has been undertaken for a series of etching parameters, including RF power, sample stage temperature, and O2 gas flow rate. Based on the experimental observations, the formation of an SiOxFy passivation layer, the rate of ion collision through the sheath field, and the silicon crystallographic orientation, are found to be the three main parameters that affect the etching process. In addition, the formation mechanism of “black silicon” (nanopillar-based Si structures) has also been proposed based on the experimental data and a simple physical model. For the purpose of silicon bulk micromachining, an optimized recipe has been developed that is suitable for the fabrication of high aspect ratio Si cantilevers on silicon-on-insulator (SOI) based waveguide wafers.

Journal of Micromechanics and Microengineering (2012). Volume 22 (9).
Publisher's version
Rights statement
Copyright © 2012 IOP Publishing. All rights reserved. Authors retain the right to place his/her postprint version of the work on a personal website or institutional repository. This article may not exactly replicate the final version published in (please see citation) as it is not a copy of this record. An electronic version of this article can be found online at: (Please see Publisher’s Version).