Parasitic charging of dielectric surfaces in capacitive microelectromechanical systems (MEMS)

Silicon dioxide and silicon nitride coatings are preferably used as dielectric layers for short-circuit protection in capacitive silicon microsensors and microactuators. However, their tendency to electrostatic charging can diminish the device reliability. Gas discharges in the air gap of silicon cantilever actuators have been observed, resulting in surface charge accumulation on the electrode passivation of the devices. Charge decay characteristics were recorded for a silicon oxide passivation and a multilayer passivation by silicon oxide and silicon nitride. The charges are found to be highly stable in time. Based on these observations, rules for the application and design of dielectric layers in microdevices are proposed.

[1]  W. von Münch,et al.  Electrostatically deflectable polysilicon torsional mirrors , 1994 .

[2]  L. Germer,et al.  Electrical Breakdown between Close Electrodes in Air , 1959 .

[3]  M. Shikida,et al.  An electrostatically actuated gas valve with an S-shaped film element , 1994 .

[4]  P. Gunther,et al.  Mechanism of charge storage in electron-beam or corona-charged silicon-dioxide electrets , 1991 .

[5]  F. Paschen,et al.  Ueber die zum Funkenübergang in Luft, Wasserstoff und Kohlensäure bei verschiedenen Drucken erforderliche Potentialdifferenz , 1889 .

[6]  Jaume Esteve,et al.  Surface micromachining technology applied to the fabrication of a FET pressure sensor , 1996 .

[7]  E. A. Amerasekera,et al.  ESD in silicon integrated circuits , 1995 .

[8]  J. A. Voorthuyzen,et al.  Semiconductor-based electret sensors for sound and pressure , 1989 .

[9]  Wouter Olthuis,et al.  A silicon condenser microphone with a silicon nitride diaphragm and backplate , 1992 .

[10]  G. Sessler,et al.  Plasma deposition of low stress electret films for electroacoustic and solar cell applications , 1996 .

[11]  William C. Tang,et al.  Electrostatic Comb Drive Levitation And Control Method , 1992 .

[12]  W. Dotzel,et al.  Silicon mirrors and micromirror arrays for spatial laser beam modulation , 1997, Proceedings of International Solid State Sensors and Actuators Conference (Transducers '97).

[13]  Lars Rosengren,et al.  Electrostatically excited diaphragm driven as a loudspeaker , 1996 .

[14]  Ernst Lueder,et al.  A surface micromachined capacitive absolute pressure sensor array on a glass substrate , 1995 .

[15]  Reimund Gerhard-Multhaupt,et al.  Silicon‐dioxide electret transducer , 1984 .

[16]  W. Sansen,et al.  A highly symmetrical capacitive micro-accelerometer with single degree-of-freedom response , 1992 .

[17]  N. F. de Rooij,et al.  Integrated circuit compatible electrostatic polysilicon microrelays , 1995 .

[18]  Jan Mehner,et al.  Silicon mirrors and micromirror arrays for spatial laser beam modulation , 1998 .