Determination of bulk discharge current in the dielectric film of MEMS capacitive switches

The present work presents a new method to calculate the discharge current in the bulk of dielectric films of MEMS capacitive switches. This method takes into account the real MEMS switch with non uniform trapped charge and air gap distributions. Assessment of switches with silicon nitride dielectric film shows that the discharge current transient seems to obey the stretched exponential law. The decay characteristics depend on the polarization field’s polarity, a fact comes along with experimental results obtained from thermally stimulated depolarization currents (TSDC) method used in MIM capacitors

Properties of contactless and contacted charging in MEMS capacitive switches

The dielectric charging in MEMS capacitive switches is a complex effect. The high electric field during pull-down causes intrinsic free charge migration and dipole orientation as well as charge injection. The macroscopic dipole moment of the first two mechanisms is opposite to the one arising from charge injection. This causes partial compensation hence mitigates the overall charging and increases the device lifetime. The charging due to intrinsic free charge migration and dipole orientation can be monitored under contactless electric field application in the pull-up state. The paper investigates the characteristics of contactless charging and compares them with the ones of contacted charging. The characteristics of the discharging process that follows each charging procedure are also presented

Field emission induced-damage in the actuation paths of MEMS capacitive structures

The field emission and resulting breakdown induced damage in the actuation paths of MEMS capacitive switches are investigated. The effect of asperities burning due to Joule heating and the resulting explosive break down are presented. The breakdown gives rise to almost mirror craters formation on the cathode and anode electrodes. A linear relation between crater diameter and the breakdown current is found when breakdown occurs in vacuum. In ambient atmosphere the breakdown leads to large amplitude current oscillations and the formation of extended damage on both electrodes. © 2020 Elsevier Lt

Investigation of charging processes in dielectrics for RF mems capacitive switches

The charging processes have been investigated in dielectrics used in RF MEMS capacitive switches. The investigation included various silicon oxides and nitrides. Finally, the effect of substrate, bottom electrode, has been taken into account

Electrical properties of nanostructured SiN films for MEMS capacitive switches

The electrical properties of gold nanorods nanostructured silicon nitride films are comprehensively investigated with the aid of metal-insulator-metal capacitors and RF MEMS capacitive switches. Different nanorod diameters and densities were grown on the bottom electrode and with orientation normal to dielectric film surface. A simple physical model, which does not take the effect of electric field fringing into account, was developed to describe both the DC and low frequency electrical properties. It has been shown that the nanorods distribution and dimensions determine the electrical properties as well as the dielectric charging phenomena of the nanostructured films. Finally, in MEMS switches it has been shown that the nanorods presence does not affect the capacitance variance nor the RF characteristics of the device. © 2016 IOP Publishing Ltd

Conduction mechanisms in conductive multi-walled carbon nanotube filled polydimethylsiloxane nanocomposites

This work presents an investigation of the electrical behavior of below percolation threshold CNTs-filled PDMS nanocomposites. Fabricated films were assessed with the aid of current-voltage characteristic and charging/discharging current transient method. The obtained results revealed the presence of a non-negligible hysteresis and the electrical conduction is found to be dominated by internal field emission processes. Finally, the role of change of direction of the applied voltage on the conduction processes has been investigated for the first time. © 2016 Elsevier B.V. All rights reserved

Investigation of Charging Processes in Dielectrics for RF MEMS Capacitive Switches

The charging processes have been investigated in dielectrics used in RF MEMS capacitive switches. The investigation included various silicon oxides and nitrides. Finally, the effect of substrate, bottom electrode, has been taken into account

Floating electrode microelectromechanical system capacitive switches: A different actuation mechanism

The paper investigates the actuation mechanism in floating electrode MEMS capacitive switches. It is demonstrated that in the pull-in state the device operation turns from voltage to current controlled actuation. The current arises from Poole-Frenkel mechanism in the dielectric film and Fowler-Nordheim in the bridge-floating electrode air gap. The pull-out voltage seems to arise from the abrupt decrease of Fowler-Nordheim electric field intensity. This mechanism seems to be responsible for the very small difference with respect to the pull-in voltage

Dielectric charging phenomena in diamond films used in RF MEMS capacitive switches: The effect of film thickness

The present paper aims to provide a better insight to the dielectric charging phenomena of nano-crystalline diamond (NCD) films that are used in RF MEMS capacitive switches. The electrical properties of NCD films of various thicknesses are investigated with the aid of metal-insulator-metal (MIM) capacitors. The dominant conduction mechanisms have been identified by obtaining current-voltage characteristics in the temperature range from 300 K to 400 K and dielectric charging phenomena have been investigated by using thermally stimulated depolarization currents (TSDC) technique. The experimental results indicate a thermally activated conductivity for low electric field intensities while Hill-type conduction takes place for field intensities > 130 kV/cm. The conductivity as well as the defect density seems to increase with film thickness. Enhanced dielectric charging phenomena have been observed on thicker films and the injected charges are found to be trapped through the material's volume. These results indicate that thinner NCD films seem to be more promising for RF MEMS capacitive switches. © 2016 Elsevier Lt

Floating electrode microelectromechanical system capacitive switches: A different actuation mechanism

The paper investigates the actuation mechanism in floating electrode MEMS capacitive switches. It is demonstrated that in the pull-in state the device operation turns from voltage to current controlled actuation. The current arises from Poole-Frenkel mechanism in the dielectric film and Fowler-Nordheim in the bridge-floating electrode air gap. The pull-out voltage seems to arise from the abrupt decrease of Fowler-Nordheim electric field intensity. This mechanism seems to be responsible for the very small difference with respect to the pull-in voltage