Acoustic microfluidic PZT transducers and temperature-compensated film bulk acoustic resonators.

摘要

This thesis presents microfluidic and Radio Frequency (RF) MicroElectroMechanical Systems (MEMS) based on Self Focusing Acoustic Transducer (SFAT) and Film Bulk Acoustic Transducer (FBAR), respectively.; The microfluidic MEMS is for Lab on Chip (LOC) or micro Total Analysis Systems (muTAS) mainly for bio-medical applications, and presents innovative ways to transfer samples among different essays in an analysis system through powerful acoustic transducers. On the other hand, the RF MEMS is mainly for wireless communication, and deals with a miniature, high quality-factor (Q acoustic resonator that can replace a ceramic or LC resonator. Specifically, this thesis covers the following two topics: PZT SFATs for fluidic handling in microfluidic MEMS and ultra temperature stable FBAR for voltage controlled oscillator over GHz.; The noninvasive PZT SFAT focuses acoustic waves on liquid surface or on any point in liquid bulk by constructive interference of acoustic waves, and produces steady body force, which moves the liquid through acoustic streaming effect. The following PZT SFATs have been developed for different functions and applications: (1) transporter and micromixer for in-plane microfluidic motion, (2) liquid droplet and needle ejector for ChemBio separation for protein and DNA separation and purification, (3) liquid atomizer for drug delivery, (4) under-water thruster, which can be used for moving a micromedical device in a blood vessel.; The temperature stable FBAR is used for Chip-Scale Atomic Clock, a miniaturized, low-power, atomic time and frequency reference unit, where a high Q resonator is needed for a local oscillator to lock into the microwave transition of the atomic clock. This thesis describes an FBAR built on a SiO2 compensated, surface micromachined diaphragm that exhibits high temperature stability, high Q and high power handling capability, which can also be used in wireless communication systems.