CAREER: Piezoelectric Microelectromechanical Systems

9501698 Kim提出通过结合压电、微机电系统（MEMS）技术和IC微制造技术来开发压电微机电系统（PMS）。 MEMS的最新发展已经开辟了许多新的应用，由于它们的小尺寸，容易形成大量的阵列，与单个芯片上的电路的可集成性，等等。然而，在MEMS中的主要活动涉及静电（或热）致动和电容（或压阻）感测，具有一些固有的特性，不适合在某些应用中。 PMS扩展了MEMS的应用领域，因为它们具有静电、热、电容或压阻MEMS所不具有的独特和有前途的特性。 所提出的研究充分利用压电驱动和传感提供的优势。 特别提出用于感测PMS的是硅上的圆顶形压电麦克风，其也可以检测声源的方向。 为了驱动PMS，提出了以下系统：1）具有波束形成和转向能力的圆顶形微扬声器和2）没有声透镜的聚焦声束发生器。 还提出了用于高频（Ghz）滤波器和振荡器的横向场激励体声波谐振器。 由于来自压电薄膜的残余应力一直是PMS的主要性能限制因素，它是建议开发（到可制造技术），我们的新想法，使用机械振动能量，以增加表面吸附原子迁移率在压电薄膜的电容器沉积残余应力减少。 提出了各种教育活动：（1）向学生展示工程是多么令人兴奋;（2）启发学生培养正确的态度（对技术问题），正确的分析技能（解决问题）独创性和终身学习的态度;（3）教授学生在固态器件领域的具体知识。 具体而言，提出了传感器和执行器的新课程。 通过拟议的大学预科教育活动，夏威夷州的公众和中学生将更接近工程学。 通过高级项目，设计项目和研究项目，学生将与行业中鼓舞人心的教授和工程师密切互动。 ***

9501698 Kim It is proposed to develop Piezoelectric Microelectromechanical Systems (PMS) through combining piezoelectricity, microelectromechanical-systems (MEMS) technology and IC-microfabrication technology. Recent development of MEMS has opened up many new applications due to their small size, easiness of forming large number of arrays, integrability with circuits on a single chip, etc. However, major activities in MEMS have involved electrostatic (or thermal) actuation and capacitive (or piezoresistive) sensing that have some inherent characteristics unsuitable in some applications. PMS expand the application areas of MEMS due to their unique and promising features that are not offered by electrostatic, thermal, capacitive, or piezoresistive MEMS. The proposed research takes full advantages offered by piezoelectric actuation and sensing. Specifically proposed for sensing PMS are dome-shaped piezoelectric microphones on silicon that can detect the direction of sound source as well. For actuating PMS, the following systems are proposed: 1) dome-shaped microspeakers with beam forming and steering capability and 2) focused acoustic beam generators without acoustic lens. Also proposed are lateral-field-excited bulk-acoustic-wave resonators for high-frequency (Ghz) filters and oscillators. Since the residual stresses coming from piezoelectric thin film has been the major performance limiting factor for PMS, it is proposed to develop (into manufacturable technology) our novel idea of using mechanical-vibrational energy to increase surface-adatom mobility during sputter-deposition of piezoelectric thin film for residual-stress reduction. Various educational activities are proposed (1)to show the students how exciting an engineering is; (2)to inspire the students to develop right attitude (toward technical problems), proper analytical skills (to solve the problems) ingenuity and life-long-learning attitude; and (3)to teach the students the specific knowledge in the area of solid-stat e devices. Specifically, new courses on sensors and actuators are proposed. Through the proposed pre-college educational activities the general public and secondary-school students in the State at Hawaii will be drawn closer to engineering. Through senior projects, design projects and research projects the students will closely interact with an inspiring professor and engineers in industry. ***