Velocity dispersion in GaN-based surface acoustic wave filters on (0001) sapphire substrates

Abstract

Abstract:We fabricated surface acoustic wave (SAW) filters on three nominally 2-µm-thick undoped GaN layers grown on (0001) sapphire substrates. We extracted SAW velocities for frequencies of the central and subsidiary peaks in the |S 21 | spectra by applying the δ-function model. We further obtained thicknesses of respective GaN layers by analysing their reflectivity spectra, and established the SAW velocity dispersion. The respective dispersion data were found to lie close to each other, which suggests that characteristics of GaN-based SAW devices can be designed with improved accuracy. Keywords: GaN, sapphire, surface acoustic wave, SAW, velocity dispersion Classification: New functional devices and materials References[1] O. Ambacher, "Growth and applications of Group III nitrides," J. Phys. D: Appl. Phys., vol. 31, no. 20, pp. 2653-2710, Oct. 1998