Flexible Lamb Wave Resonators Based On Lithium Niobate Thin Film

Flexible electronics are superior to traditional rigid electronics in terms of mechanical flexibility,weight,and size,and have received widespread attention from academics and industry.Piezoelectric resonators are one of the indispensable devices in the field of electronics.The development of flexible piezoelectric resonators came into being.The Lamb wave resonator based on lithium niobate thin film(LN-LWR)is an emerging piezoelectric MEMS resonator with high operating frequency,high K_t~2,high Q and low power consumption.The research of the LN-LWR based on silicon substrate has achieved fruitful results.However,the research of the flexible LN-LWR is still blank.In this paper,the flexible LN-LWR is studied by using Flex MEMS technology.The main research contents and results of this paper are as follows:1.Combined with the characteristics of this topic,the Flex MEMS technology was further developed,and a whole set of design methods and processing technology suitable for the fabrication of flexible LN-LWR were explored2.This work designed tether structures and circular opening holes,which fixed the position of the resonator during processing and improved the bending resistance of the resonator.The transfer of the LN-LWR from the silicon substrate to the flexible substrate with a cavity solves the problem that the lateral size of the substrate cavity is not easily limited during the fabrication of the resonator based on silicon substrate.3.Based on the optimized Flex MEMS technology,a flexible LN-LWR with excellent electrical properties was successfully demonstrated for the first time.The flexible resonator has a resonance frequency of 429 MHz,K_t~2 of 16.2%,Q of 1268,and Fo M of 205.4.This work characterized the bending characteristics of flexible resonators.After the flexible resonator is attached to a cylinder with a radius of 9mm,its electrical performance remains unchanged.After 10000 repeated bends,electrical performance is guaranteed while maintaining mechanical properties.The test results show that the flexible resonator has excellent mechanical and electrical performance stability.