Authors: J Xu JS Thakur G Hu Q Wang Y Danylyuk H Ying GW Auner
Publish Date: 2006/03/01
Volume: 83, Issue: 3, Pages: 411-415
Abstract
AlN thin films have been grown on aplane sapphire Al2O3112̄0 substrates Xray diffraction measurements indicate the films are fully cplane 0001 oriented with a full width at half maximum of the AlN0002 rocking curves of 092 The epitaxial growth relationships have been determined by the reflection high energy electron diffraction analysis as AlN11̄00//Al2O30001 and AlN112̄0//Al2O311̄00 Angular dependence of important surface acoustic wave SAW characteristics such as the phase velocity and electromechanical coupling coefficient has been investigated on the AlN0001/Al2O3112̄0 structure While the SAW is excited at all propagation angles with an angular dispersion of the phase velocity in the range of 5503–6045 m/s a higher velocity shearhorizontal SH mode is observed only at 0° 105° and 180° off the reference Al2O311̄00 over a 180° angular period The phase velocity of the SH mode shows dispersion 6089–6132 m/s as a function of the SAW wavelength Temperature coefficients of frequency are also demonstrated for both modes
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