Simulation of electrical properties of quartz crystal microbalance using multi-resonance thickness-shear mode technique

Abstract

The use of quartz crystal microbalance (QCM) in chemistry, biophysics, microbiology and electronics has grown tremendously in recent years. In this paper, the properties of a QCM sensor (a system include QCM device and viscoelastic medium) operating in the range of 5 MHz to 35 MHz of Multi-resonance Thickness-Shear Mode (MTSM, n = 1, 3, 5, 7) are described. We calculate the changes both in resonant frequencies and attenuation of the QCM. The penetration depth of the shear waves propagating from quartz into loaded thin film varies in different values due to the harmonics, from which we infer the properties of the loaded thin film. The multi-harmonic operation of QCM was presented to collect the information of the loaded thin film on QCM’s electrode. This enables a “virtual slicing technique” because a harmonic relates to a different penetration depth even with the same material. The theoretical analysis of MTSM has been developed to model and simulate the signature of the sensor responses at harmonic frequencies. The signatures of the evaporation- induced deposition processes were investigated by studying the effect of the thickness and stiffness of the medium.