Microscale friction reduction by normal force modulation in MEMS.

Friction in MEMS-scale devices is troublesome because it can result in lateral stiction of two sliding surfaces. We have investigated the effect of modulation of the normal force on the friction between two sliding MEMS surfaces, using a fully MEMS-based tribometer. We have found that the friction is reduced significantly when the modulation is large enough. A simple model is presented that describes the friction reduction as a function of modulation frequency as well. Using this technique, lateral stiction-related seizure of microscopic sliding components can be mitigated

The Leiden MEMS Tribometer: Real Time Dynamic Friction Loop Measurements With an On-Chip Tribometer

Quantum Matter and Optic

Abstract MEMS reliability from a failure mechanisms perspective

Over the last few years, considerable effort has gone into the study of the failure mechanisms and reliability of microelectromechanical systems (MEMS). Although still very incomplete, our knowledge of the reliability issues relevant to MEMS is growing. This paper provides an overview of MEMS failure mechanisms that are commonly encountered. It focuses on the reliability issues of micro-scale devices, but, for some issues, the field of their macroscopic counterparts is also briefly touched. The paper discusses generic structures used in MEMS, stiction, creep, fatigue, brittle fatigue in silicon, wear, dielectric charging, breakdown, contamination and packaging

Longer MEMS switch lifetime using novel dual-pulse voltage driver

A novel dual-pulse voltage driver has been proposed to reduce dielectric charging in micro-electromechanical system (MEMS) switch, leading to a longer switch lifetime. Mathematical and transient circuit models have been utilized to simulate dielectric charging in the RF MEMS switch, enabling the analysis of charge built-up at the switch dielectric and substrate brought about by the actuation voltage curve used. The proposed dual-pulse actuation signal has shown to improve the lifetime of the RF MEMS switch as it minimizes the charge built-up during its long continuous operation. Practical experiment on the commercial TeraVicta TT712-68CSP MEMS switch shows that the proposed actuation voltage can reduce the pull in/out voltage shift and therefore prolong the switch lifetime. The technique has also shown to reduce switching bounces

The description of friction of silicon MEMS with surface roughness: virtues and limitations of a stochastic Prandtl–Tomlinson model and the simulation of vibration-induced friction reduction

We have replaced the periodic Prandtl–Tomlinson model with an atomic-scale friction model with a random roughness term describing the surface roughness of micro-electromechanical systems (MEMS) devices with sliding surfaces. This new model is shown to exhibit the same features as previously reported experimental MEMS friction loop data. The correlation function of the surface roughness is shown to play a critical role in the modelling. It is experimentally obtained by probing the sidewall surfaces of a MEMS device flipped upright in on-chip hinges with an AFM (atomic force microscope). The addition of a modulation term to the model allows us to also simulate the effect of vibration-induced friction reduction (normal-force modulation), as a function of both vibration amplitude and frequency. The results obtained agree very well with measurement data reported previously