Temperature compensation of SAW in ZnO/SiO/sub 2//Si structure

Abstract

Temperature stability is a critical issue for SAW devices in communication and sensor applications. The negative temperature coefficient of delay (TCD) of SiO 2 makes it suitable as a compensation layer in multilayer structures where the piezoelectric layer possesses a positive TCD. In this work, the SAW propagation properties, including velocity dispersion, electro-mechanical coupling coefficients, and propagation attenuation in ZnO/SiO 2 /Si structures are investigated using the transfer matrix method. For different thickness ratios of ZnO to SiO 2 , temperature compensation of the second GSAW modes at frequencies in the range of 1GHz to 3 GHz is calculated. The simulation results show good temperature stability at 2.4 GHz when the ZnO:SiO 2 thickness ratio is 2:3 and total film thickness is 3 m.

Shear-horizontal surface acoustic wave characteristics of a (110) ZnO/SiO2/Si multilayer structure

“…Moreover, it is possible to obtain temperature compensated SAW devices in ZnO/SiO 2 /Si multilayered structure because of the opposite temperature coefficient of frequency (TCF) of ZnO and SiO 2 thin films [19][20][21].…”

Micro-hotplate based temperature stabilization system for CMOS SAW resonators

“…This paper presents two different methods of temperature compensation, which was implemented to reduce the dependency of the device's The first approach is based on the micro-oven concept of heating the device to a temperature higher than its typical operating temperature. Such method has been demonstrated to be very successful as a temperature compensation method (Wu et al 2001, Lakdawala and Fedder 2004, Ja et al 2006, Hopcroft et al 2004. A control experiment is first conducted and recorded to observe the effect of varying temperatures on the uncompensated device's resonant frequency.…”

Temperature stability of ZnO-based Love wave biosensor with SiO2 buffer layer

“…Therefore, theoretical studies are essentially required to optimize the performance of a layered SAW biosensor. There have been many reports on the ZnO/SiO 2 /Si structure sensor theoretically and experimentally [9][10][11][12][13][14], but we find that there are still some problems remaining, such as the relation among the mass loading sensitivity, temperature coefficients of delay and coupling coefficients in the optimization of Love wave biosensor and the dependence of IDTs configurations and shorting metal arrangements on TCD characteristics, both of them are meaningful and will be discussed in the following sections.…”

“…However, integration with a negative TCD material, such as SiO 2 [8,9], could make a zero TCD layered structure and reduce the thickness of ZnO thin film. Moreover, it is also found that the mass loading sensitivity can be further improved by adding the SiO 2 thin film.…”