Sub-micron gaps without sub-micron etching

Abstract

The authors present a processing technique consisting of polysilicon etching, thermal oxidation of polysilicon, and silicon dioxide wet-etching which results in the fabrication of operational, submicron gaps between the electrodes of side-drive actuators, without the need for submicron etching capability. As one example of an application of oxidation machining, this technique was used to define operational submicron gaps between the polysilicon electrodes of an electrostatic comb-drive actuator and a type of linear, side-drive actuator. Experimental results have verified the fundamental principle of the fabrication and indicate that it is possible to achieve operational gaps as small as 0.2 μm with 10,000 angstrom resolution.