Experimental surface acoustic wave properties of AlN thin films on sapphire substrates

Equivalent circuit model parameters of Rayleigh propagation along the [001] axis of AlN (110) thin films synthesized using chemical vapor deposition on a sapphire R-plane were measured. The electro-mechanical coupling constant was 0.63% at k h ≧2, and the static capacitance was 46.3 pF/m in the case that the line/space ratio was unity. The acoustic impedance and the normalized susceptance were obtained as a function of wavelength of surface acoustic wave for various line/space ratios.