Shear mode AlN thin film electro-acoustic resonant sensor operation in viscous media

Abstract A shear mode thin film bulk acoustic resonator (FBAR) operating in liquid media together with a microfluidic transport system is presented. The resonator has been fabricated utilizing a recently developed reactive sputter-deposition process for AlN thin films with inclined c-axis relative to the surface normal with a mean tilt of around 30°. The resonator has a resonance frequency of around 1.2 GHz and a Q value in water of around 150. Sensor operation in water and glycerol solutions is characterized. Theoretical analysis of the sensor operation under viscous load as well as of the sensitivity and stability in general is presented. The theoretical predictions are compared with experimental measurements. The results demonstrate clearly the potential of FBAR biosensors for the fabrication of highly sensitive low cost biosensors, bioanalytical tools as well as for liquid sensing in general.

[1]  K. Telschow,et al.  Observation of flexural modes in FBAR resonators at MHz frequencies , 2003, IEEE Symposium on Ultrasonics, 2003.

[2]  Ewald Benes,et al.  General one‐dimensional treatment of the layered piezoelectric resonator with two electrodes , 1987 .

[3]  G. Coquin,et al.  Cadmium Sulphide and Zinc Oxide Thin-Film Transducers , 1968, IEEE Transactions on Sonics and Ultrasonics.

[4]  E. Benes,et al.  Viscosity sensor utilizing a piezoelectric thickness shear sandwich resonator , 1998, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[5]  A. Spetz,et al.  Shear mode AlN thin film electroacoustic resonator for biosensor applications , 2005, IEEE Sensors, 2005..

[6]  C. D. Stockbridge,et al.  Effects of Gas Pressure on Quartz-Crystal Microbalances , 1966 .

[7]  Wolfram Wersing,et al.  Shear mode FBARs as highly sensitive liquid biosensors , 2006 .

[8]  Joel F. Rosenbaum,et al.  Bulk Acoustic Wave Theory and Devices , 1988 .

[9]  Jay W. Grate,et al.  Acoustic Wave Sensors , 1996 .

[10]  I.D. Avramov,et al.  A 0-phase circuit for QCM-based measurements in highly viscous liquid environments , 2005, IEEE Sensors Journal.

[11]  W. Simburger,et al.  Biochemical sensors based on bulk acoustic wave resonators , 2003, IEEE International Electron Devices Meeting 2003.

[12]  J.R. Vig.  On acoustic sensor sensitivity , 1991, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[13]  David S. Ballantine,et al.  Acoustic wave sensors : theory, design, and physico-chemical applications , 1997 .

[14]  G. Wingqvist,et al.  Synthesis of textured thin piezoelectric A1N films with a nonzero c-axis mean tilt for the fabrication of shear mode resonators , 2005, IEEE Ultrasonics Symposium, 2005..

[15]  Vasileios Koutsos,et al.  IEEE Ultrasonics Symposium Proceedings , 2008 .

[16]  Eun Sok Kim,et al.  Implantable resonant mass sensor for liquid biochemical sensing , 2004, 17th IEEE International Conference on Micro Electro Mechanical Systems. Maastricht MEMS 2004 Technical Digest.

[17]  Stephen J. Martin,et al.  Effect of surface roughness on the response of thickness-shear mode resonators in liquids , 1993 .