Measurement of adhesion forces between polycrystalline silicon surfaces via a MEMS double-clamped beam test structure

Abstract

An electrostatically actuated double-clamped beam test structure has been designed and fabricated for the quantitative determination of adhesion forces between two contacting polycrystalline silicon (polysilicon) surfaces. The experimental measurements of the beam profile at varied bias and simulations based on finite element methods are combined to evaluate more accurately the adhesion forces experienced between polysilicon surfaces. In particular, the electrostatic force at pull-off is obtained by measuring the pull-off voltage and the beam profile through optical interferometric methods. The adhesion force is then determined from the mechanical restoring force obtained by finite element methods simulations and the calculated electrostatic force. The results show a weak scaling of the adhesion force with the apparent contact area, defined via microfabricated dimples.

Measurement of Interfacial Adhesion Force with a 3D-Printed Fiber-Tip Microforce Sensor

“…For hydrogels and human hair on the micro scale, the surface effect is greatly enhanced due to the increase of the ratio of surface area to volume, and the surface effect will be better than the inertia effect, which makes the adhesion force become extremely important [ 1 , 4 , 39 ]. Under general environmental conditions, adhesion force has many sources, including van der Waals force, electrostatic attractive force, hydrogen bonding force, capillary force, and other interaction forces generated by the physics and chemistry of the interaction surface [ 6 ].…”

“…When the size of an object is reduced to the micro- or nanoscale, micro/nanoscale adhesion forces become extremely important because of the resulting increase in the surface area to volume ratio, and understanding of the adhesion behavior between surfaces has become an important topic [ 1 , 2 , 3 ]. Under general environmental conditions, the joint contributions of the capillary force, the electrostatic attractive force, hydrogen bonding and the van der Waals force constitutes the adhesion force [ 4 , 5 , 6 ]. Study of the adhesion forces and their molecular dynamics at interfaces is highly important in various fields, including materials science [ 7 , 8 , 9 ], biomedicine [ 10 , 11 , 12 ], aerospace [ 13 ], and micromechanics [ 14 , 15 ].…”

A finite element technique for accurate determination of interfacial adhesion force in MEMS using electrostatic actuation

“…However, the published experimental data display a notable deviation in surface energy and adhesion force for polycrystalline silicon surfaces. For example, surface energy of 13.7 to 270 mJ m −2 were reported in [7][8][9][10][11][12] and adhesion force from 17 to 32 μN for 8 × 8 μm 2 contact area were reported in [13,14] or average of 700 μN with standard deviation of 92 μN for a silicon ball of 1 mm diameter on silicon (1 0 0) wafer was reported in [15]. These deviations are attributed to different factors such as material properties, surface topography, surface termination and working conditions (humidity and temperature) that may vary from one test structure to another.…”

“…We recently reported a direct measurement of adhesion force between polysilicon surfaces using a clamped-clamped beam test structure [13,14]. In this method, the contact between the two surfaces under investigation is initiated using electrostatic actuation and is terminated by structural force stored in the beam.…”

An investigation of stiction in poly-SiGe micromirror

“…[3][4][5][6] However, most of these approaches are only evaluated on planar surfaces or simple dedicated test structures. Several experimental methods have been used to study the stiction in MEMS, including the cantilever beam array technique (CBA), atomic force microscopy (AFM), double-clamped beams and other dedicated devices [7][8][9]. Based on numbers obtained from these techniques, a wide range of adhesion force values can be found in the literature.…”