Microfabricated biaxial electrostatic torsional scanning mirror

We describe the design, fabrication and characterization of a biaxial torsional scanning mirror for use in a microfabricated confocal, optical microscope. The mirror, fabricated using wafer bonding and surface micromaching techniques, is a gimbal structure consisting of a silicon plate, measuring 500 pm x 500 mu m x 25 mu m, which is suspended in a silicon frame by silicon nitride hinges. It is actuated electrostatically, and is capable of raster scanning with a line scan frequency of 2.7 kHz and with a scan range of +/-1.5 degrees about both orthogonal axes. Both resonant and non-resonant scanning are discussed. Sample images acquired with a frame rate of 10 Hz using a microfabricated microscope with the biaxial scanning mirror are presented.