This paper investigates the dependence of dielectric charging on the pull-in state electric field... more This paper investigates the dependence of dielectric charging on the pull-in state electric field and temperature in capacitive RF MEMS switches with silicon dioxide as the dielectric material. Electric field intensities determined by bias levels extending from 0% to 50% above pull-in voltage are employed. Experimental results indicate that charging is thermally activated and the activation energy increases with increasing the intensity of the pull-in state electric field. These results provide a deeper insight to the trapping processes in dielectric materials under different levels of electric stress and aid in better modeling of charging processes in capacitive RF MEMS switches.
A method that allows the investigation of discharge transport mechanism in dielectric films used ... more A method that allows the investigation of discharge transport mechanism in dielectric films used in MEMS capacitive switches or MIM capacitors or even bare dielectric films is presented. The method is based on monitoring the dielectric film surface or MIM top electrode potential decay rate and the dependence of conductivity on surface potential. The method has been applied in MEMS and MIMs with simultaneously deposited dielectric film to confirm the closeness of transport data in MIM and MEMS devices. The impact of non-uniform charging on local discharge rate and different dielectric film stoichiometry has been also assessed. Finally, the effect of surface leakage due to environment humidity has been also investigated. [2019-0159]
Abstract The potential application of Yttrium Oxide (Y2O3) in capacitive Micro-Electro-Mechanical... more Abstract The potential application of Yttrium Oxide (Y2O3) in capacitive Micro-Electro-Mechanical Switches (MEMS) dielectric films is investigated. The electrical properties and the impact of electrical stress on capacitive switches have been investigated with the aid of Metal-Insulator-Metal (MIM) capacitors and MEMS capacitive switches in order to determine the suitability of this material for such application. The assessment in MIMs consisted of recording the current-voltage characteristics in order to determine the transport mechanisms and the charge injection by injecting electrodes during the charging process. The MEMS switches were employed to monitor the charge injection through the bridge during pull-in state and collection during the pull-up state. The process was performed under different stress conditions in order to determine the impact of stressing electric field intensity.
Abstract The present paper aims to provide a better insight to the dielectric charging phenomena ... more Abstract 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.
Abstract The present paper aims to provide a better approach on the analysis of pull-up capacitan... more Abstract The present paper aims to provide a better approach on the analysis of pull-up capacitance-voltage characteristic of MEMS capacitive switches by introducing an analytical model that takes into account the case of a real device, where the charge is not uniformly distributed at the surface of the dielectric film and the capacitor armatures are not parallel. The proposed model allows the use of capacitance-voltage characteristic's derivative, which slope is directly related to the device mechanical characteristics and the stress induced during charging. The application of the model on a MEMS switch with asymmetric capacitance-voltage characteristic and on a switch with a parabolic up-state capacitance-voltage characteristic during charging and discharging processes allows the draw of some initial conclusions on the charging and the mechanical performance of the devices. Further investigation is in progress in order to extract important information on the device degradation.
Journal of Micromechanics and Microengineering, 2016
The electrical properties of gold nanorods nanostructured silicon nitride films are comprehensive... more 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.
Abstract The present paper aims to provide a better insight on the electrical properties of silic... more Abstract The present paper aims to provide a better insight on the electrical properties of silicon nitride (SiNx) dielectric films with embedded carbon nanotubes (CNTs) that can be used in RF MEMS capacitive switches. The effect of the embedded CNTs on the leakage current density and on the discharging processes of the films has been probed with the aid of metal-insulator-metal (MIM) capacitors and it has been found that the presence of CNTs results in an increase of leakage current density as well as to an acceleration of the charge displacement through the bulk of the dielectric films. Finally, the charging and discharging processes have been investigated in MEMS capacitive switches and it has been found that the use of CNTs in SiNx films results in an enhancement of charging processes but it also accelerates the discharging process.
This paper investigates the dependence of dielectric charging on the pull-in state electric field... more This paper investigates the dependence of dielectric charging on the pull-in state electric field and temperature in capacitive RF MEMS switches with silicon dioxide as the dielectric material. Electric field intensities determined by bias levels extending from 0% to 50% above pull-in voltage are employed. Experimental results indicate that charging is thermally activated and the activation energy increases with increasing the intensity of the pull-in state electric field. These results provide a deeper insight to the trapping processes in dielectric materials under different levels of electric stress and aid in better modeling of charging processes in capacitive RF MEMS switches.
2015 IEEE International Symposium on Circuits and Systems (ISCAS), 2015
ABSTRACT In this work we investigate the dynamics of a floating electrode microelectromechanical ... more ABSTRACT In this work we investigate the dynamics of a floating electrode microelectromechanical (MEMS) switch. This is a type of very common MEMS that are actuated elecrtrostatically, i.e., by applying a voltage across the micromechanical structure. A floating electrode MEMS is a novel modification of a capacitive switch where a thin metal layer is deposited on top of the isolating dielectric layer. Although these devices have promis- ing characteristics, this modification alters their behaviour in comparison with conventional MEMS switches. We develop a multi-physics model to simulate the behaviour of the switch and model a number of physical effects that occur in the system and influence its dynamics. We used a fractal as representation of the electrode surface to model the field emission as a result of a local enhancement of the electric field. We provide the comparison of the simulated behaviour with experimental results.
This paper investigates the dependence of dielectric charging on the pull-in state electric field... more This paper investigates the dependence of dielectric charging on the pull-in state electric field and temperature in capacitive RF MEMS switches with silicon dioxide as the dielectric material. Electric field intensities determined by bias levels extending from 0% to 50% above pull-in voltage are employed. Experimental results indicate that charging is thermally activated and the activation energy increases with increasing the intensity of the pull-in state electric field. These results provide a deeper insight to the trapping processes in dielectric materials under different levels of electric stress and aid in better modeling of charging processes in capacitive RF MEMS switches.
A method that allows the investigation of discharge transport mechanism in dielectric films used ... more A method that allows the investigation of discharge transport mechanism in dielectric films used in MEMS capacitive switches or MIM capacitors or even bare dielectric films is presented. The method is based on monitoring the dielectric film surface or MIM top electrode potential decay rate and the dependence of conductivity on surface potential. The method has been applied in MEMS and MIMs with simultaneously deposited dielectric film to confirm the closeness of transport data in MIM and MEMS devices. The impact of non-uniform charging on local discharge rate and different dielectric film stoichiometry has been also assessed. Finally, the effect of surface leakage due to environment humidity has been also investigated. [2019-0159]
Abstract The potential application of Yttrium Oxide (Y2O3) in capacitive Micro-Electro-Mechanical... more Abstract The potential application of Yttrium Oxide (Y2O3) in capacitive Micro-Electro-Mechanical Switches (MEMS) dielectric films is investigated. The electrical properties and the impact of electrical stress on capacitive switches have been investigated with the aid of Metal-Insulator-Metal (MIM) capacitors and MEMS capacitive switches in order to determine the suitability of this material for such application. The assessment in MIMs consisted of recording the current-voltage characteristics in order to determine the transport mechanisms and the charge injection by injecting electrodes during the charging process. The MEMS switches were employed to monitor the charge injection through the bridge during pull-in state and collection during the pull-up state. The process was performed under different stress conditions in order to determine the impact of stressing electric field intensity.
Abstract The present paper aims to provide a better insight to the dielectric charging phenomena ... more Abstract 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.
Abstract The present paper aims to provide a better approach on the analysis of pull-up capacitan... more Abstract The present paper aims to provide a better approach on the analysis of pull-up capacitance-voltage characteristic of MEMS capacitive switches by introducing an analytical model that takes into account the case of a real device, where the charge is not uniformly distributed at the surface of the dielectric film and the capacitor armatures are not parallel. The proposed model allows the use of capacitance-voltage characteristic's derivative, which slope is directly related to the device mechanical characteristics and the stress induced during charging. The application of the model on a MEMS switch with asymmetric capacitance-voltage characteristic and on a switch with a parabolic up-state capacitance-voltage characteristic during charging and discharging processes allows the draw of some initial conclusions on the charging and the mechanical performance of the devices. Further investigation is in progress in order to extract important information on the device degradation.
Journal of Micromechanics and Microengineering, 2016
The electrical properties of gold nanorods nanostructured silicon nitride films are comprehensive... more 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.
Abstract The present paper aims to provide a better insight on the electrical properties of silic... more Abstract The present paper aims to provide a better insight on the electrical properties of silicon nitride (SiNx) dielectric films with embedded carbon nanotubes (CNTs) that can be used in RF MEMS capacitive switches. The effect of the embedded CNTs on the leakage current density and on the discharging processes of the films has been probed with the aid of metal-insulator-metal (MIM) capacitors and it has been found that the presence of CNTs results in an increase of leakage current density as well as to an acceleration of the charge displacement through the bulk of the dielectric films. Finally, the charging and discharging processes have been investigated in MEMS capacitive switches and it has been found that the use of CNTs in SiNx films results in an enhancement of charging processes but it also accelerates the discharging process.
This paper investigates the dependence of dielectric charging on the pull-in state electric field... more This paper investigates the dependence of dielectric charging on the pull-in state electric field and temperature in capacitive RF MEMS switches with silicon dioxide as the dielectric material. Electric field intensities determined by bias levels extending from 0% to 50% above pull-in voltage are employed. Experimental results indicate that charging is thermally activated and the activation energy increases with increasing the intensity of the pull-in state electric field. These results provide a deeper insight to the trapping processes in dielectric materials under different levels of electric stress and aid in better modeling of charging processes in capacitive RF MEMS switches.
2015 IEEE International Symposium on Circuits and Systems (ISCAS), 2015
ABSTRACT In this work we investigate the dynamics of a floating electrode microelectromechanical ... more ABSTRACT In this work we investigate the dynamics of a floating electrode microelectromechanical (MEMS) switch. This is a type of very common MEMS that are actuated elecrtrostatically, i.e., by applying a voltage across the micromechanical structure. A floating electrode MEMS is a novel modification of a capacitive switch where a thin metal layer is deposited on top of the isolating dielectric layer. Although these devices have promis- ing characteristics, this modification alters their behaviour in comparison with conventional MEMS switches. We develop a multi-physics model to simulate the behaviour of the switch and model a number of physical effects that occur in the system and influence its dynamics. We used a fractal as representation of the electrode surface to model the field emission as a result of a local enhancement of the electric field. We provide the comparison of the simulated behaviour with experimental results.
Uploads
Papers by Matroni Koutsoureli