Low-Actuation Voltage MEMS Digital-to-Analog Converter with Parylene Spring Structures

Cheng-Wen Ma; Fu-Wei Lee; Hsin-Hung Liao; Wen-Cheng Kuo; Yao-Joe Yang

doi:10.3390/s150921567

Low-Actuation Voltage MEMS Digital-to-Analog Converter with Parylene Spring Structures

Sensors (Basel). 2015 Aug 28;15(9):21567-80. doi: 10.3390/s150921567.

Authors

Cheng-Wen Ma¹, Fu-Wei Lee², Hsin-Hung Liao³, Wen-Cheng Kuo⁴, Yao-Joe Yang⁵

Affiliations

¹ Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan. jeson@mems.me.ntu.edu.tw.
² Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan. fuweilee1221@mems.me.ntu.edu.tw.
³ Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan. ice@mems.me.ntu.edu.tw.
⁴ Department of Mechanical and Automation Engineering and Graduate Institute of Industrial Design, National Kaohsiung First University of Science and Technology, Kaoshiung 824, Taiwan. rkuo@ccms.nkfust.edu.tw.
⁵ Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan. yjy@ntu.edu.tw.

Abstract

We propose an electrostatically-actuated microelectromechanical digital-to-analog converter (M-DAC) device with low actuation voltage. The spring structures of the silicon-based M-DAC device were monolithically fabricated using parylene-C. Because the Young's modulus of parylene-C is considerably lower than that of silicon, the electrostatic microactuators in the proposed device require much lower actuation voltages. The actuation voltage of the proposed M-DAC device is approximately 6 V, which is less than one half of the actuation voltages of a previously reported M-DAC equipped with electrostatic microactuators. The measured total displacement of the proposed three-bit M-DAC is nearly 504 nm, and the motion step is approximately 72 nm. Furthermore, we demonstrated that the M-DAC can be employed as a mirror platform with discrete displacement output for a noncontact surface profiling system.

Keywords: digital-to-analog converter; electrostatic microactuators; microelectromechanical systems; micromirror; parylene; white-light interferometry.