Theoretical and experimental investigation of gigahertz-band, temperature-compensated electromechanical coupling configurations based on AlN films

Highly c-axis oriented piezoelectric AlN films were sputtered on (0001) Al2O3 substrates and four gigahertz-range surface acoustic wave (SAW) electroacoustic coupling configurations were realized by conventional photolithographic process. The thermal sensitivity of each device was experimentally estimated and found in good accordance with the theoretical predictions. Eight gigahertz-range, thermally compensated SAW devices were obtained for specific AlN thickness, SAW propagation direction, and electrical boundary conditions. A theoretical analysis of the acoustic and electrical behavior of the four coupling structures is proposed to match the achievable performances of the SAW devices with the design requirements.

[1]  Omar Elmazria,et al.  Surface acoustic wave propagation in aluminum nitride-unpolished freestanding diamond structures , 2002 .

[2]  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 .

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

[4]  P. Muralt,et al.  Solidly mounted BAW filters for 8 GHz based on AlN thin films , 2003, IEEE Symposium on Ultrasonics, 2003.

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

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

[7]  K. Lakin,et al.  Numerical analysis of thin film BAW resonators , 2003, IEEE Symposium on Ultrasonics, 2003.

[8]  K. Sugai,et al.  Zero Temperature Coefficient Surface-Acoustic-Wave Devices Using Epitaxial AlN Films , 1982 .

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

[10]  Oliver Brandt,et al.  Superhigh-frequency surface-acoustic-wave transducers using AlN layers grown on SiC substrates , 2002 .

[11]  K. Kim,et al.  Crystallographic characteristics and effective electromechanical coupling coefficients of AlN thin films for FNAR applications , 2003, IEEE Symposium on Ultrasonics, 2003.

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