Mechanical stiffness and dissipation in ultrananocrystalline diamond microresonators

作     者：V. P. Adiga A. V. Sumant S. Suresh C. Gudeman O. Auciello J. A. Carlisle R. W. Carpick 

作者机构：Department of Materials Science and Engineering University of Pennsylvania Philadelphia Pennsylvania 19104 USA Center for Nanoscale Materials Argonne National Laboratory Argonne Illinois 60439 USA Innovative Micro Technology Santa Barbara California 93117 USA Materials Science Division Argonne National Laboratory Argonne Illinois 60439 USA Advanced Diamond Technologies Romeoville Illinois 60446 USA Department of Mechanical Engineering and Applied Mechanics University of Pennsylvania Philadelphia Pennsylvania 19104 USA 

出 版 物：《Physical Review B》 (物理学评论B辑：凝聚态物质与材料物理学)

年 卷 期：2009年第79卷第24期

页      面：245403-245403页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：DARPA [06-W238] U. S. Department of Energy [DE-AC02-06CH05117] Office of Science Office of Basic Energy Sicences [DE-AC02-06CH11357] 

主　　题：atomic force microscopy cantilevers chemical vapour deposition compressive strength defect states diamond EXAFS internal stresses lithography micromechanical resonators nanoelectromechanical devices nanostructured materials Poisson ratio Q-factor stress relaxation thin films XANES Young's modulus 

摘      要：We have characterized mechanical properties of ultrananocrystalline diamond (UNCD) thin films grown using the hot filament chemical vapor deposition (HFCVD) technique at 680 °C, significantly lower than the conventional growth temperature of ∼800 °C. The films have ∼4.3% sp2 content in the near-surface region as revealed by near edge x-ray absorption fine structure spectroscopy. The films, ∼1 μm thick, exhibit a net residual compressive stress of 370±1 MPa averaged over the entire 150 mm wafer. UNCD microcantilever resonator structures and overhanging ledges were fabricated using lithography, dry etching, and wet release techniques. Overhanging ledges of the films released from the substrate exhibited periodic undulations due to stress relaxation. This was used to determine a biaxial modulus of 838±2 GPa. Resonant excitation and ring-down measurements in the kHz frequency range of the microcantilevers were conducted under ultrahigh vacuum (UHV) conditions in a customized UHV atomic force microscope system to determine Young’s modulus as well as mechanical dissipation of cantilever structures at room temperature. Young’s modulus is found to be 790±30 GPa. Based on these measurements, Poisson’s ratio is estimated to be 0.057±0.038. The quality factors (Q) of these resonators ranged from 5000 to 16000. These Q values are lower than theoretically expected from the intrinsic properties of diamond. The results indicate that surface and bulk defects are the main contributors to the observed dissipation in UNCD resonators.