The dual-mode SAW device using IDT/ZnO/AlN/Si3N4/Si structure

• Main Authors: Guan-ting Peng, 彭冠庭
• Other Authors: Ying-Chung Chen
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/7nff93

碩士 === 國立中山大學 === 電機工程學系研究所 === 102 === In this study, dual-mode (Rayleigh-mode and Sezawa-mode) surface acoustic wave (SAW) devices using IDT/ZnO/AlN/Si3N4/Si structure were fabricated. To fabricate dual-mode SAW Devices, the RF magnetron sputtering method for the growth of piezoelectric thin films (AlN and ZnO) onto Si3N4/Si are adopted and influences of the sputtering parameters are investigated. The preferred orientation and crystalline properties of the piezoelectric thin films were evaluated by X-ray diffraction (XRD).The cross–sectional image of the piezoelectric thin films were observed by scanning electron microscopy which revealed a high c-axis preferred orientation. The surface roughness of ZnO/AlN thin films were observed by atomic force microscopy (AFM) and the surface roughness is 7.644 nm. After the ZnO/AlN thin films were deposited, Al layer was deposited onto the ZnO/AlN this films, by a DC sputtering system, and the interdigital transducers (IDTs) using the photolithography method were defined. The frequency response is measured using an E5071C network analyzer. The frequency response of the fundamental wave mode (Rayleigh-mode) of 144.03 MHz is obtained；the high order frequency response of Sezawa mode (Sezawa-2 mode) of 273.09 MHz is obtained；the insertion loss of Rayleigh-mode and Sezawa-2 mode are -12.4 dB and -15.8 dB respectively.