A Micromachined Valve for Power MEMS
X. Yang (J. Lang, M.A. Schmidt, and S. Umans)
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.
Fig. 29: N2 flow-rate versus actuation voltage for the valve as a func-
tion of inlet pressure.