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Title: Lubrication of polysilicon micromechanisms with self-assembled monolayers

Abstract

Here, the authors report on the lubricating effects of self-assembled monolayers (SAMs) on MEMS by measuring static and dynamic friction with two polysilicon surface- micromachined devices. The first test structure is used to study friction between laterally sliding surfaces and with the second, friction between vertical sidewalls can be investigated. Both devices are SAM-coated following the sacrificial oxide etch and the microstructures emerge released and dry from the final water rinse. The coefficient of static friction, {mu}{sub s} was found to decrease from 2.1 {+-} 0.8 for the SiO{sub 2} coating to 0.11 {+-} 0.01 and 0.10 {+-} 0.01 for films derived from octadecyltrichloro-silane (OTS) and 1H,1H,2H,2H-perfluorodecyl-trichlorosilane (FDTS). Both OTS and FDTS SAM-coated structures exhibit dynamic coefficients of friction, {mu}{sub d} of 0.08 {+-} 0.01. These values were found to be independent of the apparent contact area, and remain unchanged after 1 million impacts at 5.6 {micro}N (17 kPa), indicating that these SAMs continue to act as boundary lubricants despite repeated impacts. Measurements during sliding friction from the sidewall friction testing structure give comparable initial {mu}{sub d} values of 0.02 at a contact pressure of 84 MPa. After 15 million wear cycles, {mu}{sub d} was found to rise to 0.27.more » Wear of the contacting surfaces was examined by SEM. Standard deviations in the {mu} data for SAM treatments indicate uniform coating coverage.« less

Authors:
; ; ; ;  [1]; ;  [2]
  1. Berkeley Sensor and Actuator Center, CA (United States)
  2. Sandia National Labs., Albuquerque, NM (United States)
Publication Date:
Research Org.:
Sandia National Labs., Albuquerque, NM (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States); National Science Foundation, Washington, DC (United States)
OSTI Identifier:
671989
Report Number(s):
SAND-98-0848C; CONF-980638-
ON: DE98004530; BR: DP0102031; TRN: AHC2DT07%%148
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Technical Report
Resource Relation:
Conference: 1998 solid state sensor and actuator workshop, Hilton Head, SC (United States), 1 Jun 1998; Other Information: PBD: Jun 1998
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; ACTUATORS; LUBRICANTS; MINIATURIZATION; LUBRICATION; SILICON; FRICTION; SILICON OXIDES; WEAR; MOTORS; EXPERIMENTAL DATA

Citation Formats

Srinivasan, U, Foster, J D, Habib, U, Howe, R T, Maboudian, R, Senft, D C, and Dugger, M T. Lubrication of polysilicon micromechanisms with self-assembled monolayers. United States: N. p., 1998. Web. doi:10.2172/671989.
Srinivasan, U, Foster, J D, Habib, U, Howe, R T, Maboudian, R, Senft, D C, & Dugger, M T. Lubrication of polysilicon micromechanisms with self-assembled monolayers. United States. https://doi.org/10.2172/671989
Srinivasan, U, Foster, J D, Habib, U, Howe, R T, Maboudian, R, Senft, D C, and Dugger, M T. Mon . "Lubrication of polysilicon micromechanisms with self-assembled monolayers". United States. https://doi.org/10.2172/671989. https://www.osti.gov/servlets/purl/671989.
@article{osti_671989,
title = {Lubrication of polysilicon micromechanisms with self-assembled monolayers},
author = {Srinivasan, U and Foster, J D and Habib, U and Howe, R T and Maboudian, R and Senft, D C and Dugger, M T},
abstractNote = {Here, the authors report on the lubricating effects of self-assembled monolayers (SAMs) on MEMS by measuring static and dynamic friction with two polysilicon surface- micromachined devices. The first test structure is used to study friction between laterally sliding surfaces and with the second, friction between vertical sidewalls can be investigated. Both devices are SAM-coated following the sacrificial oxide etch and the microstructures emerge released and dry from the final water rinse. The coefficient of static friction, {mu}{sub s} was found to decrease from 2.1 {+-} 0.8 for the SiO{sub 2} coating to 0.11 {+-} 0.01 and 0.10 {+-} 0.01 for films derived from octadecyltrichloro-silane (OTS) and 1H,1H,2H,2H-perfluorodecyl-trichlorosilane (FDTS). Both OTS and FDTS SAM-coated structures exhibit dynamic coefficients of friction, {mu}{sub d} of 0.08 {+-} 0.01. These values were found to be independent of the apparent contact area, and remain unchanged after 1 million impacts at 5.6 {micro}N (17 kPa), indicating that these SAMs continue to act as boundary lubricants despite repeated impacts. Measurements during sliding friction from the sidewall friction testing structure give comparable initial {mu}{sub d} values of 0.02 at a contact pressure of 84 MPa. After 15 million wear cycles, {mu}{sub d} was found to rise to 0.27. Wear of the contacting surfaces was examined by SEM. Standard deviations in the {mu} data for SAM treatments indicate uniform coating coverage.},
doi = {10.2172/671989},
url = {https://www.osti.gov/biblio/671989}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1998},
month = {6}
}