Papers by Matroni Koutsoureli
Mitigation of Dielectric Charging in MEMS Capacitive Switches with Stacked TiO2/Y2O3 Insulator Film
International Symposium for Testing and Failure Analysis, 2018
Metal-insulator-metal (MIM) capacitors with single TiO2 and a TiO2/Y2O3 stack are used as insulat... more Metal-insulator-metal (MIM) capacitors with single TiO2 and a TiO2/Y2O3 stack are used as insulator films in MIM and MEMS, respectively, are explored. It is found that, under electron injection from bottom electrode, the TiO2 MIM capacitors demonstrate resistive switching with a magnitude of leakage currents not usable for MEMS application. The deposition of a stacked TiO2/Y2O3 dielectric film improves the MEMS performance without compromising the low dielectric charging of TiO2 single layer.
MEMS容量性スイッチにおける誘電体帯電持続的信頼性問題,可給態モデルと評価法【Powered by NICT】
MEMS容量性スイッチの誘電体帯電評価のためのプルアップ容量‐電圧特性の深さの解析【Powered by NICT】
Microelectronics Reliability, 2016
A novel method for the assessment of surface charge density variance in capacitive RF-MEMS switches
Microelectronics Reliability, 2021
A study of hopping transport during discharging in SiNx films for MEMS capacitive switches
Microelectronics Reliability, 2020
Abstract A more realistic approach of the discharging process in MEMS capacitive switches is pres... more Abstract A more realistic approach of the discharging process in MEMS capacitive switches is presented with the introduction of the effective temperature in order to determine the behavior of the microscopic parameters of hopping conduction, which dominates the process. The use of Kelvin Probe method in MIM capacitors that simulates the discharging process in MEMS switches during up-state revealed that both the increase of temperature and stressing field intensity results the decrease of mean hopping length. This result arises from the simultaneous contribution of the transport energy levels associated with the impact of the stressing field and temperature. Also, a correlation was found experimentally between the stretched exponential decay and the hopping process. The proposed method was also applied in MEMS switches where a similar behavior of the hopping parameters was found, providing evidence that the control of the hopping length to an optimum value can provide fast discharging and low leakage currents, increasing the device lifetime.
Temperature accelerated discharging processes through the bulk of PECVD silicon nitride films for MEMS capacitive switches
Microelectronics Reliability, 2017
Abstract The effect of temperature on discharging processes of PECVD silicon nitride films has be... more Abstract The effect of temperature on discharging processes of PECVD silicon nitride films has been investigated in Metal-Insulator-Metal (MIM) capacitors and RF MEMS capacitive switches with the aid of Kelvin Probe method. The surface potential decay of MIM capacitors during discharge has been monitored using a Single-point Kelvin probe system at various temperatures (300 K–400 K) while the shift of bias at minimum up-state capacitance during discharge has been employed in MEMS capacitive switches in order to determine the discharge current through the bulk of the film at different temperatures. The results indicate that the discharging process through the bulk of silicon nitride films is thermally activated and the corresponding value of the discharging current increases with temperature, due to the increase of the film conductivity. Moreover, the value of minimum up-state capacitance of the switches is found to be significantly affected by temperature, by the mechanical properties of the moving armature as well as by the variance of charge density distribution. Finally, different thermally activated mechanisms have been observed in MIM capacitors and MEMS capacitive switches, due to different charging processes on these devices.
Dielectric charging in MEMS capacitive switches a persisting reliability issue, available models and assessment methods
2016 16th Mediterranean Microwave Symposium (MMS), 2016
The reliability issue of dielectric charging in MEMS capacitive switches is discussed taking into... more The reliability issue of dielectric charging in MEMS capacitive switches is discussed taking into account the present knowledge derived from the numerous papers on this topic. The weakness of the available charge injection model is pointed, the dependence of the material stoichiometry with film thickness resulting in lateral charge redistribution is discussed, the available assessment techniques are presented and the discharge process through the dielectric film is analyzed.
Dielectric Charging Asymmetry in SiN Films Used in RF MEMS Capacitive Switches
IEEE Transactions on Device and Materials Reliability, 2017
This paper presents a systematic investigation of the effect of stressing bias polarity to the di... more This paper presents a systematic investigation of the effect of stressing bias polarity to the discharge process of plasma enhanced chemical vapor deposition SiN films that have been fabricated under different deposition conditions. Dielectric charging asymmetry has been observed on the utilized films of metal-insulator-metal capacitors and microelectromechanical systems capacitive switches, since charging is enhanced when negative polarization bias is applied to the top electrode. In addition, it is shown that deposition conditions play a key issue role on the degree of this asymmetry. Finally, a physical model which assumes that hopping dominates the discharging process is used in order to gain a better understanding of the processes that are responsible for the appearance of asymmetric dielectric charging and the results correlate with the material’s electrical properties.
Asymmetric dielectric charging phenomena on SiN films used in RF MEMS capacitive switches
2015 Asia-Pacific Microwave Conference (APMC), 2015
The present paper investigates the effect of stressing bias polarity to the discharge process of ... more The present paper investigates the effect of stressing bias polarity to the discharge process of PECVD SiN films that takes place through the bulk of the dielectric film, with the aid of Kelvin Probe method, and the results are correlated to the material's properties. A new physical model is used in order to gain a better understanding to the processes that are responsible for the appearance of asymmetric dielectric charging on these films. The proposed model can be also used to predict the time evolution of discharging processes on dielectric films with known characteristics and therefore to be included in device reliability modeling.
Optimization of Dielectric Material Stoichiometry for High-Reliability Capacitive MEMS Switches
IEEE Microwave and Wireless Components Letters, 2016
This letter examines the effect of dielectric material stoichiometry and substrate temperature on... more This letter examines the effect of dielectric material stoichiometry and substrate temperature on the charging performance and reliability of capacitive MEMS switches with silicon nitride. Various dielectric stoichiometries were obtained by varying the deposition temperature and gas flow ratios during the PECVD deposition process. Results from both MIM capacitors and MEMS switches have shown that charging is mitigated in silicon nitride films deposited at 150 °C with a high ratio of nitrogen to silicon content (N/Si = 0.98).
Microelectronics Reliability, 2015
Contact-less charging process has been found to constitute a compensation mechanism to dielectric... more Contact-less charging process has been found to constitute a compensation mechanism to dielectric charging of MEMS capacitive switches. The present paper aims to provide a better knowledge of induced charging mechanisms that appear in HF PECVD silicon nitride films. The characteristics of this process as well as the degree of compensation are investigated for different stressing field intensities of both polarities in MEMS capacitive switches. The experimental results indicate that the degree of compensation in HF PECVD SiN x films seems to increase with the intensity of the applied electric field and it is also affected by the polarity of the stressing bias. A new theoretical model that describes the build-up of induced charging is also proposed. Taking into account that the electric field during contact-less charging is quite low, the model assumes that induced charging arises from charge displacement inside the film through hopping conduction processes.
Journal of Micromechanics and Microengineering, 2014
The paper presents the electrical assessment and modeling of the discharge process in RF-MEMS cap... more The paper presents the electrical assessment and modeling of the discharge process in RF-MEMS capacitive switches with nanocrystalline diamond dielectric film. The assessment is performed by taking into account the detailed DC electrical characterization of the dielectric film at different temperatures with the aid of Metal-Insulator-Metal capacitors fabricated on the same die. The model assumes screening of trapped charges through carriers that are injected from bottom electrode, transported through grain boundaries and redistributed across diamond film surface through sp 2 state of non diamond carbon. Simulated data and experimental results are found to be in excellent agreement clearly indicating that nanocrystalline diamond can be considered as a MEMS dielectric with predictable discharging process.
Assessment of dielectric charging in RF MEMS capacitive switches with the aid of MIM capacitors
2014 29th International Conference on Microelectronics Proceedings - MIEL 2014, 2014
ABSTRACT Dielectric charging is an important reliability issue for RF MEMS capacitive switches st... more ABSTRACT Dielectric charging is an important reliability issue for RF MEMS capacitive switches still preventing their commercialization. Therefore a lot of effort has been spent on the understanding of charging and discharging processes. MIM capacitors are considered as equally important device for the assessment of dielectric charging for RF MEMS. Beside the obvious similarities between MEMS switches in the down state and MIM capacitors there are also some important differences. The present papers aims to reveal the similarities and the differences between the two types of devices by analyzing experimental data obtained on MIM capacitors and MEMS capacitive switches fabricated with the same material.
A study of deposition conditions on charging properties of PECVD silicon nitride films for MEMS capacitive switches
Microelectronics Reliability, 2014
ABSTRACT The present paper aims to provide a better insight to the electrical characteristics of ... more ABSTRACT The present paper aims to provide a better insight to the electrical characteristics of silicon nitride films that have been deposited with PECVD method under different conditions. The effect of film thickness, substrate temperature and the frequency that produces the plasma in PECVD method on the dielectric charging phenomenon in silicon nitride films has been investigated with the aid of thermally stimulated depolarization currents (TSDC) and Kelvin Probe (KP) techniques. The results indicate that the decrease of film thickness and substrate temperature as well as the deposition at high frequency plasma (13.56 MHz) seems to produce silicon nitride films that are less prone to dielectric charging and thus better candidates for MEMS capacitive switches.
Probing contactless injection dielectric charging in RF MEMS capacitive switches
Electronics Letters, 2014
ABSTRACT Dielectric charging is a major reliability issue preventing commercialisation of RF MEMS... more ABSTRACT Dielectric charging is a major reliability issue preventing commercialisation of RF MEMS capacitive switches. To date two major modes have been considered as responsible for the charging of the dielectric films in RF MEMS. The one takes place during the pull-down state and therefore it is called contacted or injection charging, whereas the second occurs when the bridge is still in the up state and is referred to as contactless or induced charging. Experimental results supporting contactless charge injection as an additional charging mechanism in RF MEMS capacitive switches are presented.
2012 IEEE International Reliability Physics Symposium (IRPS), 2012
Model of a capacitive switch with non-uniform trapped charge and air gap distributions [14].
Alpha particle radiation effects in RF MEMS capacitive switches
Microelectronics Reliability, 2008
The paper investigates the effect of 5MeV alpha particle irradiation in RF MEMS capacitive switch... more The paper investigates the effect of 5MeV alpha particle irradiation in RF MEMS capacitive switches with silicon nitride dielectric film. The investigation included MIM capacitors in order to obtain a better insight on the irradiation introduced defects in the dielectric film. The ...
Facta universitatis - series: Electronics and Energetics, 2013
The assessment of dielectric charging in MEMS capacitive switches is investigated. The informatio... more The assessment of dielectric charging in MEMS capacitive switches is investigated. The information can be obtained only from simultaneous assessment of Metal-Insulator-Metal capacitance and MEMS capacitive switches the former allowing the determination of material properties and the latter of the device.
Temperature dependence of the conduction mechanisms through a Pb(Zr,Ti)O3 thin film
Thin Solid Films, 2014
ABSTRACT The conduction mechanisms through a lead zirconate titanate (PZT) thin film grown by pul... more ABSTRACT The conduction mechanisms through a lead zirconate titanate (PZT) thin film grown by pulsed laser deposition with a La0.67Sr0.33MnO3 (LSMO) buffer layer on epitaxial Pt (111) were assessed in the 230–330 K temperature range. X-Ray diffraction and transmission electron microscopy evidenced a columnar growth of (001)- and (011)-oriented PZT grains. The leakage current through the Pt/PZT/LSMO/Pt structure was then systematically measured. From current vs. time curves, a threshold voltage was found below which stable and reproducible current values are obtained, thus avoiding resistance degradation. The conduction mechanism changes from interface controlled at low temperatures to bulk controlled around room temperature. The hopping-type conductivity evidenced above 270 K is consistent with the extended defects and columnar microstructure of the PZT film.
Microelectronics Reliability, 2013
The dielectric charging in MEMS capacitive switches is a complex effect. The high electric field ... more 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.
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Papers by Matroni Koutsoureli