Shear Mode AlN Thin Film Electroacoustic Resonator for Biosensor Applications

Abstract

A thin film thickness excited shear acoustic wave resonator is presented. Utilizing a newly developed reactive sputtering process AlN thin films with inclined c-axis relative to the surface normal with a mean tilt of around 30° are successfully grown. Using the above process, a biosensor consisting of a shear mode thin film bulk acoustic resonator (FBAR) and a microfluidic transport system was fabricated. The biosensor operation in water, glycerol and albumin was characterized. The resonator had a resonance frequency of around 1.2 GHz and a Q value in water of around 150. Results concerning the stability and resolution are also presented. 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.

Novel semiconductor materials for the development of chemical sensors and biosensors: A review

“…AlN [84][85][86][87][88] GaAs [89] netic interference (EMI), while the devices based on them can operate at higher frequencies. This unique chemical, physical and mechanical stability make these new semiconductor materials ideal for the development of specific chemical sensor and biosensor systems.…”

Nanomechanical properties of AlN(103) thin films by nanoindentation

“…Very recently, a two-stage sputtering process to deposit tilted AlN films to form a quasi (1 0 3)-AlN texture is proposed by Bjurstrom et al [6,7]. The resulting film had a distinct tilted texture with the mean tilt of the c-axis varying roughly in the interval 28-32 • over the wafer.…”

Comparison of FBAR and QCM-D sensitivity dependence on adlayer thickness and viscosity

“…Piezoelectric thin-films with the c-axis being inclined from the film normal were developed to achieve sufficiently high piezoelectric shear coupling coefficients (Wang and Lakin, 1982;Carlotti et al, 1990;Akiyama et al, 2004;Martin et al, 2005;Wingqvist et al, 2005;Link et al, 2006b;Yanagitani et al, 2007;Fardeheb-Mammeri et al, 2008) While the working principle of FBAR and QCM is similar, the QCM is produced in a top-down process and FBARs in a bottom-up process using thinfilm technology. As a result FBARs can be made thinner, which results in a higher resonance frequency.…”