IC-processed electrostatic micro-motors

The authors describe the design, fabrication, and operation of several micromotors that have been produced using integrated-circuit processing. Both rotors and stators for these motors, which are driven by electrostatic forces, are formed from 1.0-1.5- mu m-thick polycrystalline silicon. The diameters of the rotors in the motors tested are between 60 and 120 mu m. Motors with several friction-reducing designs have been fabricated using phosphosilicate glass (PSG) as a sacrificial material and either one or three polysilicon depositions. Examples of stepping and three-phase synchronous drive micromotors are described. Typical drive voltages for present designs exceed 100 V. Manually switched motors have tested at speeds up to 12 r.p.m. Synchronous motors have been driven at speeds to 500 r.p.m.<>