maboudianlab - Di Gao

Alumnus - Ph.D.

Ph.D. in Chemical Engineering, University of California, Berkeley, 2004

B.S. in Chemical Engineering and Computer Science and Technology , Tsinghua University, China, 1999

Current Position:

Assistant Professor
Department of Chemical and Petroleum Engineering
1249 Benedum Hall
University of Pittsburgh
Pittsburgh, Pennsylvania 15261

Personal Webpage

Silicon Carbide Materials for MEMS Applications

Silicon carbide (SiC) is a promising material for micro- and nano-electromechanical systems (MEMS and NEMS) operating in harsh environments, characterized by locations exposed to high temperature, strong radiation, intense vibration, and corrosive and abrasive media. This is due to the excellent electrical, mechanical and chemical properties of SiC. Compared with Si, SiC has a significantly larger energy band gap and breakdown field. It is hard, and wear resistant second only to diamond. SiC is inert to most chemicals at room temperature and has been found to be a biocompatible material. SiC has also gained attention because of the extensive interest in ultra-high frequency MEMS and NEMS for wireless signal-processing systems. SiC has a higher acoustic velocity (defined as the square root of Young’s modulus to mass density ratio) than Si, which can be translated directly to higher resonant frequencies for the same device dimensions. The extremely stable physicochemical properties of SiC also improve the performance of high-frequency resonators as the surface-to-volume ratio increases when the resonator frequency scales into GHz ranges.

The purpose of my research is to develop manufacturable SiC microfabrication technologies suitable for MEMS and NEMS applications, including chemical vapor deposition, selective reactive ion etching, and integration of SiC micromachining with conventional microfabrication processes. During the process development, the mechanical, electrical and chemical properties of SiC thin films are systematically characterized using state-of-the-art material characterization technologies, as well as MEMS testing microstructures. The SiC microfabrication technologies are applied to build SiC nanoelectromechanical filter arrays for RF wireless communication systems.

Ph.D. Thesis

Silicon carbide technology for micro- and nano-electromechanical systems applications (2004)

Advisors: Prof.'s Roya Maboudian and Roger T. Howe.