Investigation into the Minimum Feature Size for Reactive-Ion Etched (RIE) Micro and Nano-Scale Polycrystalline Diamond Mechanical Resonators

Mcglone, A. W., Williams, O. A. and Moran, D. A. J. (2015) Investigation into the Minimum Feature Size for Reactive-Ion Etched (RIE) Micro and Nano-Scale Polycrystalline Diamond Mechanical Resonators. In: MRS Fall Meeting: Materials Research Society, Boston MA, USA, 29 Nov - 4 Dec 2015,

Abstract

Owing to its unique mechanical properties such as high acoustic velocity (18,024 m/s) [1] and high thermal conductivity (2100 W/mK) [2], diamond is an attractive candidate for use in micro-electro-mechanical systems (MEMS) devices and is implemented in numerous ways including micro-switching and mass detection. Reported is a process developed to fabricate and characterise cantilever shaped resonant structures of varying mass and dimension. Polycrystalline diamond samples with grain size sub-500 nm are produced by microwave plasma chemical vapour deposition on a silicon substrate in a 1% CH4/H2 environment. Samples are patterned using a Vistec VB6 UHR EWF electron beam lithography tool. Using an Al or HSQ mask, the patterned samples are etched in an RIE tool with an O2/Ar gas mixture returning an anisotropy of ~80˚. The etched diamond structures are released from the silicon substrate by wet etching the sample in KOH. The mass of the structures are scaled down until mechanical failure is observed, demonstrated by degradation of frequency response and Q factor. The structures are actuated in air by mechanical force from either compressed air or a piezo clamp and resonant frequency and Q factor observed by means of a vibrometer. Experimental results are compared with simulations and sample specific values for Young’s modulus are reported.

• Item Type: Conference Proceedings
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Mcglone, Mr Andrew and Moran, Professor David
• Authors: Mcglone, A. W., Williams, O. A., and Moran, D. A. J.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering

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