Love-mode surface acoustic wave devices based on multilayers of TeO 2 /ZnO(112¯0)/Si(100) with high sensitivity and temperature stability

• Published in: Ultrasonics 2017-03, Vol.75, p.63
• Main Authors: Luo, Jing-Ting, Quan, Ao-Jie, Liang, Guang-Xing, Zheng, Zhuang-Hao, Ramadan, Sami, Fu, Chen, Li, Hong-Lang, Fu, Yong-Qing
• Format: Article
• Language: English
• ISSN: 1874-9968

A multilayer structure of TeO /interdigital transducers (IDTs)/ZnO(112¯0)/Si(100) was proposed and investigated to achieve both high sensitivity and temperature-stability for bio-sensing applications. Dispersions of phase velocities, electromechanical coupling coefficients K , temperature coefficient of delay (TCD) and sensitivity in the multilayer structures were simulated as functions of normalized thicknesses of ZnO (h /λ) and TeO (h /λ) films. The fundamental mode of Love mode (LM) - surface acoustic wave (SAW) shows a larger value of K and higher sensitivity compared with those of the first mode. TeO film with a positive TCD not only compensates the temperature effect induced due to the negative TCD of ZnO(112¯0)/Si(100), but also enhances the sensitivity of the love mode device. The optimal normalized thickness ratios were identified to be h /λ=0.021 and h /λ=0.304, and the devices with such structures can which generate a normalized sensitivity of -1.04×10 m /kg, a TCD of 0.009ppm/°C, and a K value of 2.76%.