Departmental Papers (ESE)

Abstract

This work presents the design and demonstration of a microscale inverse acoustic band gap (IABG) structure in aluminum nitride (AlN) with a frequency stop band for bulk acoustic waves in the very high frequency range. Conversely to conventional microscale acoustic band gaps, the IABG is formed by a two-dimensional periodic array of unit cells consisting of a high acoustic velocity material cylinder surrounded by a low acoustic velocity medium. The periodic arrangement of the IABG array induces scattering of incident acoustic waves and generates a stop band, whose center frequency is primarily determined by the lattice constant of the unit cell and whose bandwidth depends on the cylinder radius, the film thickness, and the size of the tethers that support the cylinder. A wide band gap (>13% of the center frequency) is formed by the IABG even when thin AlN films are used. The experimental response of an IABG structure having a unit cell of 8.6 µm and an AlN film thickness of 2 µm confirms the existence of a frequency band gap between 185 MHz and 240 MHz.

Document Type

Journal Article

Date of this Version

9-2-2009

Comments

Copyright 2009 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. Reprinted from:

Microscale inverse acoustic band gap structure in aluminum nitride Nai-Kuei Kuo, Chengjie Zuo, and Gianluca Piazza, Appl. Phys. Lett. 95, 093501 (2009), DOI:10.1063/1.3213345
Publisher URL: http://link.aip.org/link/?APPLAB/95/093501/1

Keywords

acoustic wave velocity, aluminium compounds, energy gap, III-V semiconductors, lattice constants, semiconductor thin films

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Date Posted: 01 October 2009

This document has been peer reviewed.