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Title: Adhesion of polysilicon microbeams in controlled humidity ambients

The authors characterize in-situ the adhesion of surface micromachined polysilicon beams subject to controlled humidity ambients. Beams were freed by supercritical CO{sub 2} drying. Consistent adhesion results were obtained using a post-treatment in an oxygen plasma which rendered the microbeams uniformly hydrophilic. Individual beam deformations were measured by optical interferometry after equilibration at a given relative humidity (RH). Validation of each adhesion measurement was accomplished by comparing the deformations with elasticity theory. The data indicates that adhesion increases exponentially with RH from 30% to 95%, with values from 1 mJ/m{sup 2} to 50 mJ/m{sup 2}. Using the Kelvin equation, the authors show that the data should be independent of RH if a smooth interface is considered. By modeling a rough interface consistent with atomic force microscopy (AFM) data, the exponential trend is satisfactorily explained.
Authors:
; ; ;
Publication Date:
OSTI Identifier:
658196
Report Number(s):
SAND--98-1034C; CONF-980405--
ON: DE98005456; BR: YN0100000; TRN: AHC2DT06%%80
DOE Contract Number:
AC04-94AL85000
Resource Type:
Technical Report
Resource Relation:
Conference: Spring meeting of the Materials Research Society, San Francisco, CA (United States), 13-17 Apr 1998; Other Information: PBD: Apr 1998
Research Org:
Sandia National Labs., Albuquerque, NM (United States)
Sponsoring Org:
USDOE Assistant Secretary for Management and Administration, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; SILICON; POLYCRYSTALS; ADHESION; HUMIDITY; SURFACE PROPERTIES; MACHINE PARTS; MINIATURIZATION; EXPERIMENTAL DATA