Micro/nano-tribological characteristics of self-assembled monolayer and its application in nano-structure fabrication

Sung, In-Ha; Yang, Ji Chul; Kim, Dae Eun; Shin, Bo Sung

doi:10.1016/s0043-1648(03)00058-9

Cited by 59 publications

(30 citation statements)

References 37 publications

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“…1) of the FOTS characteristics (0.13) is significantly greater than that of the ODTS characteristics (0.042). These values compare well with those reported by others [2,7,11,13,15,32] for -CF 3 , -CH 3 terminated self-assembled monolayers. Figure 3 shows that the friction-velocity relationship is logarithmic for both the test molecules at room temperature at two different normal loads.…”

Section: Resultssupporting

confidence: 91%

“…This model suggests that higher the adhesion, higher is the friction force. The friction of CF terminated monolayers is found to be greater [2][3][4][5][6][7][8] than that of CH terminated monolayers although the adhesion of the former is [9][10][11] less than or similar to that of the latter. As fluroalkyl and alkane are important tribological molecules, this anomaly has given rise to much debate.…”

Section: Introductionmentioning

confidence: 78%

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Use of Eyring Equation to Explore the Frictional Responses of a –CF3 and a –CH3 Terminated Monolayers Self-Assembled on Silicon Substrate

et al. 2008

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Lateral force microscopy is used to measure the frictional forces generated in sliding a silicon nitride tip on perflurooctyl trichlorosilane (FOTS) and octadecyltrichlorosilane (ODTS) monolayers self-assembled (SAM) on silicon wafer. The work is motivated by a need to rationalize the high friction of FOTS in comparison to that found for ODTS, inspite of the former having a low surface energy compared to that of the latter. Having first established that the tribology here is a thermally activated process, we use the Eyring equation to estimate the energetic barrier height to sliding motion, system activation energy, shear coordination and pressure activation volumes. For a molecular species when the velocity and temperature are unchanged in a sliding experiment and the activation energy remains unchanged the change in shear coordination with increasing normal load controls the friction coefficient. In comparing the performance of the two test molecules the friction coefficient of the FOTS is found to be three times greater than that of the ODTS; the corresponding difference in barrier height is about 10%. Our results indicate that when the two molecules are well ordered, the shear coordination modulates the frictional differential but it is the difference in their system activation energy, principally determined by electrostatic repulsion between the neighbouring molecules which is a dominant influence on their friction differential.

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Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 78%

Use of Eyring Equation to Explore the Frictional Responses of a –CF3 and a –CH3 Terminated Monolayers Self-Assembled on Silicon Substrate

et al. 2008

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“…It is known that the adhesion [9,10] and surface energy [11] of CF 3 terminated molecules are somewhat less than that of a CH 3 terminated molecule although there appears to be some experimental evidence to the contrary [3,4]. Lateral Force microscopy studies [1,2,5] however clearly demonstrated that friction corresponding to the former is significantly higher than that of the latter. Now it is established that molecular conformation of backbone has a profound effect on tribology [12], higher entropy generation and diminishing packing density [13,14] promotes higher friction.…”

Section: Introductionmentioning

confidence: 99%

“…We have therefore looked for additive molecules with head groups which can reactively anchor on these surfaces. Commercially available organosilane additive are being considered presently [1][2][3][4][5][6] for lubrication of semiconductor silicon surfaces and components in electronic packaging, micro electro-mechanical system and information storage. We consider these molecules here as possible boundary lubrication additive for aluminium based components in moving machinery.…”

Section: Introductionmentioning

confidence: 99%

Frictional Responses of Octadecyltrichlorosilane (OTS) and 1H, 1H, 2H, 2H-Perfluorooctyltrichlorosilane (FOTS) Monolayers Self-assembled on Aluminium over Six Orders of Contact Length Scale

2005

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We have measured the frictional responses of two silane molecules (Octadecyltrichlorosilane; OTS and 1H, 1H, 2H, 2H-Perfluorooctyltrichlorosilane; FOTS) self-assembled on an aluminium substrate in their non heat-treated and heat-treated states. We varied the contact length scale by performing the experiments in atomic force microscope, nanotribometer and macro scale pinon-disc machine. We have found that conformational disorder and molecular stiffness have major influences on friction in strongly distinguishing the response of OTS from that of the FOTS molecules. The frictional identity between the two molecules before and after heat treatment, though somewhat contrary to that suggested from purely surface energy considerations, is found to hold over six orders of contact length scales, ten orders of normal load and in three vastly different contact conditions; (a) the probe penetrates about 25% of the molecular backbone of a SAM; no substrate deformation, (b) the contact of the probe with the SAM is conformal and the substrate is plastically deformed and (c) the molecule is dispersed in 5% (v/v) concentration in n-hexadecane to lubricate a pin-on-disc contact.

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“…Previous studies showed that the so-called mechano-chemical process is a rapid, cost-effective, and reliable method for fabrication of micro-scale structures on silicon surface [29][30][31]. The strategy for fabricating nano-structures on a metal surface is to scribe away the SAM resist using a sharp tip where pattern formation by subsequent chemical etching was desired.…”

Section: Introductionmentioning

confidence: 99%

Surface Damage Characteristics of Self-Assembled Monolayers of Alkanethiols on Metal Surfaces

Sung

Kim

2004

Tribology Letters

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The effect of metal oxide layer on the nano-tribological characteristics of single chain alkanethiol (CH 3 (CH 2 ) n SH) selfassembled monolayers (SAMs) on various metal surfaces (gold, silver, copper) was investigated. In order to correlate the surface structures with the tribological characteristics, various surface analysis techniques such as Scanning Probe Microscopy, X-ray Photoelectron Spectroscopy, Secondary Ion Mass Spectrometry and Spectroscopic Ellipsometry were used. Results of surface analyses showed that thiols on a metal surface were susceptible to forming multilayers if the metal surface was oxidized before the thiol assembly process. From the friction and wear tests conducted using an Atomic Force Microscope and a Lateral Force Microscope, it was found that thiols on copper oxide surface could be easily removed even under a few nano-Newton normal load. On the other hand, thiols on gold and copper fresh surfaces (the surface which was made by minimizing oxide formation) could endure up to micro-Newton level loads. Based on these findings, it could be concluded that the nano-tribological characteristics of alkanethiol SAMs on various metal surfaces were largely dependent on the oxide layer that already formed on the metal surface before the thiol adsorption process.

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Micro/nano-tribological characteristics of self-assembled monolayer and its application in nano-structure fabrication

Cited by 59 publications

References 37 publications

Use of Eyring Equation to Explore the Frictional Responses of a –CF3 and a –CH3 Terminated Monolayers Self-Assembled on Silicon Substrate

Use of Eyring Equation to Explore the Frictional Responses of a –CF3 and a –CH3 Terminated Monolayers Self-Assembled on Silicon Substrate

Frictional Responses of Octadecyltrichlorosilane (OTS) and 1H, 1H, 2H, 2H-Perfluorooctyltrichlorosilane (FOTS) Monolayers Self-assembled on Aluminium over Six Orders of Contact Length Scale

Surface Damage Characteristics of Self-Assembled Monolayers of Alkanethiols on Metal Surfaces

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