TY - JOUR
T1 - Characterization of a MEMS tribogauge
AU - Vijayasai, Ashwin
AU - Sivakumar, Ganapathy
AU - Ramachandran, Gautham
AU - Anderson, Charlie
AU - Gale, Richard
AU - Dallas, Tim
N1 - Funding Information:
The authors acknowledge support from a National Science Foundation MRI grant ( CBET #0821162 ) and Sandia National Labs for fabricating the MEMS chips used in this work. The authors would like to thank Manjula Wickramasinghe and Dr. Jordan Berg, Department of Mechanical Engineering, Texas Tech University, for donating the AD7747-EB board; SEM/TEM images provided by Charles Linch, Texas Tech University Health Sciences Center Imaging Center.
PY - 2013/1/25
Y1 - 2013/1/25
N2 - A MEMS tribogauge was used for on-chip and in-situ characterization of nano-tribological phenomena (stiction, friction, and wear). The measurements were made on the sidewall surfaces on the tribogauge at the third structural polysilicon layer in the device. The device consists of two orthogonally oriented comb-drive mechanisms that are used for both actuation and sensing functions. One actuator applies a normal load (Fn) to a contacting surface, while the other actuator induces a tangential load (FT). A LabVIEW controlled AD7747 capacitance sensor is used to measure the position of the interacting surfaces. This data is converted into adhesive force information. The spatial resolution of the characterization apparatus is ±10nm. Experiments were conducted with tribogauges with and without a self-assembled monolayer (SAM) coating. The SAM coatings being explored have a fluorocarbon tail group. The tribogauge with no SAM coating is UV/Ozone cleaned to remove organic contaminants. The tribogauge characterization includes: measurement of baseline stiction force FbaselineFOTS, static (FS) and dynamic (FD) coefficient of friction, and induced stiction force FinducedFOTS. The UV/Ozone treated tribogauge was used to measure the baseline stiction force. Additional experiments showed that the induced stiction force increases in proportion to the increase in the number of load cycles, indicating degradation of the SAM coating and inducing surface topographical changes to the interacting surfaces.
AB - A MEMS tribogauge was used for on-chip and in-situ characterization of nano-tribological phenomena (stiction, friction, and wear). The measurements were made on the sidewall surfaces on the tribogauge at the third structural polysilicon layer in the device. The device consists of two orthogonally oriented comb-drive mechanisms that are used for both actuation and sensing functions. One actuator applies a normal load (Fn) to a contacting surface, while the other actuator induces a tangential load (FT). A LabVIEW controlled AD7747 capacitance sensor is used to measure the position of the interacting surfaces. This data is converted into adhesive force information. The spatial resolution of the characterization apparatus is ±10nm. Experiments were conducted with tribogauges with and without a self-assembled monolayer (SAM) coating. The SAM coatings being explored have a fluorocarbon tail group. The tribogauge with no SAM coating is UV/Ozone cleaned to remove organic contaminants. The tribogauge characterization includes: measurement of baseline stiction force FbaselineFOTS, static (FS) and dynamic (FD) coefficient of friction, and induced stiction force FinducedFOTS. The UV/Ozone treated tribogauge was used to measure the baseline stiction force. Additional experiments showed that the induced stiction force increases in proportion to the increase in the number of load cycles, indicating degradation of the SAM coating and inducing surface topographical changes to the interacting surfaces.
KW - Adhesion force
KW - Coatings
KW - Friction
KW - MEMS
KW - Stiction
KW - Tribology
UR - http://www.scopus.com/inward/record.url?scp=84872674997&partnerID=8YFLogxK
U2 - 10.1016/j.surfcoat.2012.07.089
DO - 10.1016/j.surfcoat.2012.07.089
M3 - Article
AN - SCOPUS:84872674997
SN - 0257-8972
VL - 215
SP - 306
EP - 311
JO - Surface and Coatings Technology
JF - Surface and Coatings Technology
ER -