Abstract: A monolithic, bi-directional micro device formed on a support base, for example a silicon wafer, including at least one input and output flow channels for flow of fluid. The actuator portion includes electrically conducting upper lower diaphragms (preferably formed from doped polycrystalline silicon) formed about a central electrode and mounted on the base. The diaphragms move under electrostatic force between first and second positions upon application of voltage. The upper and lower diaphragms form a sealed, enclosed cavity separated from the channels. The diaphragms are connected for mechanically transmitting electrostatically induced force from one diaphragm to the other, preferably by one or more posts passing through at least one hole formed in the central electrode. The lower diaphragm and the support base are maintained at the same electrical potential. The device is formed by depositing and patterning the electrodes and forming spaces between the electrodes by etching of sacrificial layers.