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Optimization of Reactive Ion Etching of Polycrystalline Diamond for MEMS Applications

MetadataDetails
Publication Date2015-09-29
JournalJournal of Microelectromechanical Systems
AuthorsZongliang Cao, Michael Varney, Dean M. Aslam
InstitutionsMichigan State University
Citations1

It has been found that diamond columns can be formed unintentionally in reactive ion etching (RIE) with O <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;2&lt;/sub> plasma even without a precoated metal layer. The experimental results indicate that the existence of these diamond columns prevents the effective removal of polycrystalline diamond (poly-C), also known as microcrystalline diamond. A three-step sequential RIE of poly-C thin film in CF <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;4&lt;/sub> (or CF <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;4&lt;/sub> /Ar), O <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;2&lt;/sub> , and H <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;2&lt;/sub> plasmas is developed using lithographically patterned Al acting as a hard mask to achieve a smooth-etched surface after the removal of poly-C. This etching technique can remove a thick poly-C layer very effectively. For the first time, this letter eliminates RIE-related damage to underlying substrate (specific to RIE of poly-C) to optimize the technology for single- and multi-material MEMS made from poly-C. [2015-0141]