Fabrication of micromechanical devices from polysilicon films with smooth surfaces

H. Guckel, J. J. Sniegowski, T. R. Christenson, S. Mohney, T. F. Kelly

Research output: Chapter in Book/Report/Conference proceedingChapter


Micromechanical devices such as bearings require smooth surfaces. Fine-grained polysilicon can be produced with a surface roughness near 8 Å rms. The ability to anneal films of this type into tension eliminates size restrictions due to compressive buckling. The use of these films in micromechanical devices has been restricted because hydrogen fluoride-etched structures are covered by an etch residue that leads to contact welding. Contact between opposing .surfaces is induced mainly by surface tension effects. This problem may be avoided by removing the deflection mechanism. Thus, freezing of a water-methanol rinse after sacrificial etching all but eliminates surface tension. Removal of the ice mixture via sublimation at 0.15 millibar occurs readily. Free-standing structures with smooth surfaces and small gaps are next passivated by silicon nitride deposition or other techniques.

Original languageEnglish (US)
Title of host publicationMicromechanics and MEMS
Subtitle of host publicationClassic and Seminal Papers to 1990
PublisherWiley-IEEE Press
Number of pages6
ISBN (Electronic)9780470545263
ISBN (Print)0780310853, 9780780310858
StatePublished - Jan 1 1997

All Science Journal Classification (ASJC) codes

  • General Computer Science
  • General Engineering
  • General Physics and Astronomy
  • General Energy


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