Analysis of the acoustoelectric behavior of microwave frequency, temperature-compensated AlN-based multilayer coupling configurations

Piezoelectric AlN films, 1.3–6.2 μm thick, have been grown on bare and metallized Al2O3(0001) substrates by reactive radio-frequency-sputtering technique at 180 °C. The films were uniform, stress-free, highly c-axis oriented normal to the surface, and extremely adhesive to the substrates. Surface acoustic wave (SAW) delay lines, showing harmonic modes with operating frequencies up to about 2.44 GHz, were obtained just using conventional optical lithography at 7.5 μm linewidth resolution. Four interdigital transducer (IDT)/counter electrode configurations were obtained locating the IDTs either on the AlN free surface or at the Al2O3/AlN interface, with and without an Al thin metal film opposite the IDTs. The temperature induced shift of the fundamental and harmonic operating frequencies of the four configurations was measured at different temperatures in the range from −25 to 70 °C. The first order temperature coefficient of delay (TCD) of the four structures was experimentally evaluated for different film...

[1]  C. Caliendo Analysis of dispersive electroacoustic coupling configurations for application to gigahertz-band, temperature-compensated AlN-based acoustic devices , 2008 .

[2]  Cinzia Caliendo,et al.  Theoretical and experimental investigation of gigahertz-band, temperature-compensated electromechanical coupling configurations based on AlN films , 2008 .

[3]  Naoteru Shigekawa,et al.  Temperature Dependence of Surface Acoustic Wave Characteristics of GaN Layers on Sapphire Substrates , 2005 .

[4]  C. Caliendo,et al.  Structural, optical, and acoustic characterization of high-quality AlN thick films sputtered on Al2O3(0001) at low temperature for GHz-band electroacoustic devices applications , 2004 .

[5]  C. Caliendo Gigahertz-band electroacoustic devices based on AlN thick films sputtered on Al2O3 at low temperature , 2003 .

[6]  Hadis Morkoç,et al.  Nitride Semiconductors and Devices , 1999 .

[7]  N. Fujimori,et al.  Theoretical study on SAW characteristics of layered structures including a diamond layer , 1995, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[8]  G. Elko,et al.  Principles of acoustic devices , 1985, Proceedings of the IEEE.

[9]  K. Tsubouchi,et al.  Zero-Temperature-Coefficient SAW Devices on AlN Epitaxial Films , 1985, IEEE Transactions on Sonics and Ultrasonics.

[10]  G. Kino,et al.  Theory of interdigital couplers on nonpiezoelectric substrates , 1973 .

[11]  R. Bechmann,et al.  Numerical data and functional relationships in science and technology , 1969 .

[12]  Allan D. Pierce,et al.  Physical acoustics : principles and methods , 1965 .