Contact angle influence on the pull-in voltage of microswitches in the presence of capillary and quantum vacuum effects

Abstract

Capillary condensation between the electrodes of microswitches influences the effective pull-in voltage in a manner that depends on the contact angle of the capillary meniscus and the presence of plate surface roughness. Indeed, surface roughening is shown to have a stronger influence on the pull-in potential for relatively small contact angles with respect to that of a flat surface when capillary condensation takes place. For long wavelength roughness ratios w / Ӷ 1 with w the rms roughness amplitude and the in-plane correlation length, the pull-in voltage increases with increasing theoretical contact angle 0 for flat surfaces. With decreasing correlation length ͑increasing roughness͒, the pull-in potential decreases faster for smaller contact angles 0 In addition, with decreasing roughness exponent H ͑0 Ͻ H Ͻ 1͒, which characterizes short wavelength roughness fluctuation at short length scales ͑Ͻ ͒, the pull-in potential shows a steeper decrease with decreasing correlation length . Finally, with increasing relative humidity, the sensitivity of the pull-in voltage at small correlation lengths attenuates significantly with increasing contact angle 0 .

Precision measurements of the gradient of the Casimir force between ultraclean metallic surfaces at larger separations

“…Because of this, it has long been proposed [33] that the next generation of micro-and nanodevices will exploit the Casimir force for their functionality. In the early twenty first century, extensive studies of the role of Casimir force in microdevices have been conducted and a lot of devices driven by the Casimir force, such as oscillators, switches, microchips etc., have been proposed [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48].…”

Reducing detrimental electrostatic effects in Casimir-force measurements and Casimir-force-based microdevices

“…[13,14] before the first microdevices driven by the Casimir force were demonstrated [17,18]. This gave impetus to research devoted to the role of stiction [19,20], electrostatic effects [21], surface roughness [22][23][24], geometry and dielectric properties of materials [25,26], and phase transformations [27] in nanotechnological systems exploiting the Casimir force for their functionality. Various possibilities to create the Casimir switch have also been discussed [28,29].…”

Casimir and Van Der Waals Forces: Advances and Problems

“…The problems of tribology on microscales await for their resolution with the use of repulsive Casimir force predicted for different nanomaterials [97] and ferromagnetic dielectrics [68]. The Casimir force has already found applications in microswitches [98,99] and is investigated in order to avoid pull-in and stiction in microdevices [100]. As was argued in Sec.6, further investigations and applications of graphene and other carbon nano-structures are also closely connected with the Casimir physics.…”