Valve For Power Mems

A Micromachined Valve for Power MEMS Personnel X. Yang (J. Lang, M.A. Schmidt, and S. Umans) Sponsorship ARO A micromachined valve is being developed that could be used as the gas fuel delivery valve for a power MEMS device. The electrostatically-actuated valve is fabricated through the aligned bonding of three silicon wafers which have been patterned using DRIE. A mid- dle wafer forms the moving part of the valve which is comprised of a boss supported by four thin tethers. Upon the application of a voltage between the boss and either the upper or lower wafer, the boss will move upward to open the valve or downward to seal the Fig 26: The three-layer microvalve. valve against a polysilicon coated seal-ring. The polysil- icon provides a defined level of surface roughness which helps to reduce valve sticking. The valve has been successfully operated to 10 atm inlet pressure with actuation voltages between 100-200V. Leak rates are Fig. 27: A schematic cross section of the valve. Fig. 28: SEM images of the three layers of the microvalve, as well as below the measurement capability. continued Fig. 29: N2 flow-rate versus actuation voltage for the valve as a func- tion of inlet pressure.

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