Jong Duk Lee

Polysilicon surface-modification technique to reduce sticking of microstructures

Abstract A new and simple surface-modification technique is proposed to reduce sticking of microstructures fabricated by surface micromachining. This technique realizes a very rugged surface at the polysilicon substrate, resulting in reduced sticking through a decrease of real contact area. The surface, which consists of honeycomb-shaped grain holes at the polysilicon substrate layer, is defined by a two-step dry etch without an additional masking step for photolithography or deposition of thin films. By varying the time for etching the grain holes of the polysilicon substrate, controlled surface roughness can be obtained. Test structures, including polysilicon cantilever beams of various lengths, fabricated by surface micromachining with the proposed surface modification show a doubled detachment length without sticking to the substrate.

Polysilicon Surface Modification Technique To Reduce Sticking Of Microstructures

A new and simple surface modification technique is proposed to reduce sticking of microstructures fabricated by surface micromachining. This technique realizes very rugged surface at substrate polysilicon, resulting in reduced sticking through decrease of real contact area. The surface, which consists of honeycomb shaped grain holes at the substrate polysilicon layer, is defined by two-step dry etch without additional masking step for photolithography nor deposition of thin films. By varying the time for etching grain holes of substrate polysilicon, controlled surface roughness can be obtained. Test structures, including various length of polysilicon cantilever beams and micro bridges, fabricated by surface micromachining with proposed surface modification shows twice increase of detachment length without sticking to substrate.