Analysis of a comb-drive actuator taking the depletion layer into consideration

Shinji Ueki, Yuki Nishimori, Hiroshi Imamoto, Tomohiro Kubota, Masakazu Sugiyama, Seiji Samukawa, Gen Hashiguchi

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


We have analyzed the effect of penetration of the electric fieldinto the semiconductor on the electrical and mechanical characteristics of comb-drive actuators. In this study we found two specific effects due to the depletion layer: (1) the electro-mechanical conversion factor is a function of the depletion layer and becomes smaller than that for the "ideal conductor" assumption, and (2) an additional stiffness appears in the mechanical system. Following the change in the electro-mechanical conversion factor, the resonance peak becomes lower than that of an ideal conductor. These effects are relatively small when the gap between the comb-fingers and the substrate is of the order of a micrometer. However if the gap is 0.1 μm, the electromechanical conversion factor decreases by about 2.8%. In this analysis, we have taken only the depletion effect into account; howeverfor a more complete analysis we should also consider the surface traps induced by unpassivated surface bonds.

Original languageEnglish
Pages (from-to)388-393
Number of pages6
JournalIEEJ Transactions on Sensors and Micromachines
Issue number8
Publication statusPublished - 2010


  • Comb-Drive Actuator
  • Depletion Layer
  • Electrostatic Actuator

ASJC Scopus subject areas

  • Mechanical Engineering
  • Electrical and Electronic Engineering


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