Papers by Author: Christian A. Zorman

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Authors: Chien-Hung Wu, Juyong Chung, Moon Hi Hong, Christian A. Zorman, P. Pirouz, Mehran Mehregany
Authors: Christian A. Zorman, Mehran Mehregany
Authors: Andrew C. Barnes, Christian A. Zorman, Philip X.L. Feng
Abstract: We report an initial experimental exploration of engineering very thin, suspended amorphous silicon carbide (a-SiC) membranes into vibrating micromechanical devices. We show that micromachined a-SiC thin square membranes can make interesting multiple-mode flexural resonators, with frequency spectra exhibiting many measurable resonant modes over a wide frequency range (100kHz–10MHz) in the low radio frequency (RF) bands. Initial demonstration and preliminary data suggest interesting and rich dynamical, nonlinear, and dissipative properties in these micromechanical resonances. Specifically, for instance, at room temperature (T≈300K) and in moderate vacuum (e.g., ~20mTorr), resonant modes of an a-SiC square membrane (thickness: t≈1.5µm, size: 1mm×1mm) are observed in the ~100kHz–5MHz range, with measured quality factors (Q’s) in the range of ~2,500–9,000.
Authors: Christian A. Zorman, Abigail Eldridge, Jian Gang Du, Matt Johnston, Anna Dubnisheva, Sargum Manley, William Fissell, Aaron Fleischman, Shuvo Roy
Abstract: This paper details the development of amorphous hydrogenated silicon carbide (a-SiC:H) films as structural material that is resistant to biofouling. The a-SiC:H films were deposited by PECVD and evaluated for their mechanical and anti-biofouling properties. It was found that the as-deposited films exhibited compressive residual stresses that could be converted to moderate tensile stresses upon a post deposition anneal. The amorphous films exhibited a much lower Young’s modulus but similar burst stress when compared to polycrystalline 3C-SiC films of like thickness. The as-deposited a-SiC:H films were more resistant to biofouling than silicon and silicon dioxide surfaces. Coating the a-SiC:H films with polyethylene glycol (PEG) significantly improved the anti-fouling characteristics for extended periods.
Authors: A.J. Fleischman, S. Roy, Christian A. Zorman, Mehran Mehregany
Authors: J. Dunning, Xiao An Fu, Mehran Mehregany, Christian A. Zorman
Abstract: This paper details the characterization of polycrystalline SiC (poly-SiC) thin films deposited by low pressure chemical vapor deposition. Films were deposited on both Si and SiO2- coated Si substrates using dichlorosilane (SiH2Cl2) and acetylene (C2H2) as precursor gases. Low residual tensile stress films were deposited at 900°C at a pressure of 2 Torr using SiH2Cl2 and C2H2 (5% in H2) flow rates of 35 sccm and 180 sccm, respectively. XRD analysis of these films indicated a (111) 3C-SiC orientation regardless of substrate material. Both resistivity (1.3 -cm) and residual stress gradient (17 MPa/μm) were found to be relatively low and decreased as the film thickness increased. Unintentional nitrogen doping is responsible for the low resistivity measurements and its concentration in the films was about 1.86 x 1016 cm-3. Poly-SiC films exhibiting near-zero residual tensile stress, low stress gradient and relatively low resistivity have favorable properties for design and fabrication of MEMS devices.
Authors: Chien-Hung Wu, Christian A. Zorman, Mehran Mehregany
Authors: J. Dunning, Xiao An Fu, Srihari Rajgopal, Mehran Mehregany, Christian A. Zorman
Authors: Xiao An Fu, J. Dunning, Christian A. Zorman, Mehran Mehregany
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