Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published June 24, 2009 | public
Journal Article

Alumina etch masks for fabrication of high-aspect-ratio silicon micropillars and nanopillars


We introduce using sputtered aluminum oxide (alumina) as a resilient etch mask for fluorinated silicon reactive ion etches. Achieving selectivity of 5000:1 for cryogenic silicon etching and 68:1 for SF_6/C_4F_8 silicon etching, we employ this mask for fabrication of high-aspect-ratio silicon micropillars and nanopillars. Nanopillars with diameters ranging from below 50 nm up to several hundred nanometers are etched to heights greater than 2 µm. Micropillars of 5, 10, 20, and 50 µm diameters are etched to heights of over 150 µm with aspect ratios greater than 25. Processing and characterization of the sputtered alumina is also discussed.

Additional Information

© 2009 IOP Publishing Ltd. Received 6 April 2009, in final form 7 April 2009. Published 2 June 2009. David Henry gratefully acknowledges and thanks the Hertz Foundation for their support. This material is based upon work supported by National Science Foundation under the DMR- 012096 and ECS-0622228 award grants.

Additional details

August 20, 2023
March 5, 2024