The Experts below are selected from a list of 1170 Experts worldwide ranked by ideXlab platform

P.j. George - One of the best experts on this subject based on the ideXlab platform.

  • A novel method to predict the effect of static charges on the pull-in voltage and touch-point pressure of the capacitive transducer with Square Diaphragm
    International Journal of Advances in Engineering Sciences and Applied Mathematics, 2010
    Co-Authors: Anurekha Sharma, P.j. George
    Abstract:

    Microelectromechanical systems (MEMS) use silicon based dielectric films such as SiO2 and Si3N4 for providing insulation. In capacitive transducers, these layers are used as insulation layers for capacitive actuators to prevent short-circuiting of electrodes by contact of electrodes and in case of touchmode capacitive pressure sensors (TMCPS), the dielectric layer provides for overload protection and provides for operation in the pressure ranges in which the Diaphragm comes in contact with dielectric. The pressure at which Diaphragm just touches the dielectric is referred to as touch-point pressure. In case of actuator, pull-in voltage is a critical parameter that decides the onset of instability in operation of the device. Silicon based dielectric thin films have the tendency to store or trap static charges, the presence of which alters the ideal behaviour of dielectrics. These trapped static charges introduced due fabrication processes; handling and operation affect the operation of capacitive transducers by influencing the pull-in voltage and by affecting the touch-point pressure. This paper presents a novel methodology, which predicts the pull-in voltage and touch-point pressure in presence of the static charges in a dielectric. The method proposed is less complex and less time consuming. Closed form expressions have been derived for pull-in voltage, touch-point pressure and critical displacement in presence of static charges. The results are compared with those obtained by experiment.

  • A simple method for calculation of the pull-in voltage and touch-point pressure for the small deflection of Square Diaphragm in MEMS
    Sensors and Actuators A-physical, 2008
    Co-Authors: Anurekha Sharma, P.j. George
    Abstract:

    There are a number of MEMS structures that make use of Diaphragms. The deformation of the Diaphragm for the purpose of actuation and transduction can be brought about by application of voltage and/or pressure or any other mechanical excitation like acceleration, force, etc. The amount of deformation can be measured by changes in the capacitance between the Diaphragm and the fixed electrode. The gap between the electrodes can be an air gap or can have an intervening layer of the dielectric on the fixed electrode along with the air gap. The pull-in voltage and touch-point pressure along with the structural and material properties are critical parameters that decide the behavior of the actuator/transducer. This paper presents a simple methodology, which is capable of representing small deflection of Diaphragm with pressure, and/or applied voltage. The method proposed is less complex and less time consuming in comparison with FEM tools. Closed form expressions have been derived for pull-in voltage with/without dielectric between the two electrodes and critical distance for pull-in. The closed form expressions for touch-point pressure have also been derived. The results are compared with those obtained by simulation as well as experiment.

Shams M Nateri - One of the best experts on this subject based on the ideXlab platform.

  • modeling of capacitance and sensitivity of a mems pressure sensor with clamped Square Diaphragm
    International Journal of Engineering, 2013
    Co-Authors: Ahram Azizollah Ganji, Shams M Nateri
    Abstract:

    In this paper, for the first time, the modeling of capacitance and sensitivity for MEMS capacitive pressure sensor with clamped Square Diaphragm is presented. In capacitive sensor the sensitivity is proportional to deflection and capacitance changes with pressure. Therefore, first the Diaphragm displacement, capacitance and sensitivity of sensor with Square Diaphragm have been modeled and then simulated using finite element method (FEM). It can be seen that the analytical results agree with simulation. The results also show that the high sensitivity can be achieved by decreasing the Diaphragm thickness and increasing its size.

Anurekha Sharma - One of the best experts on this subject based on the ideXlab platform.

  • a modified method to model the effect of residual stress on touch point pressure and pull in voltage for mems capacitive transducers using Square Diaphragm
    Iete Journal of Research, 2011
    Co-Authors: Anurekha Sharma
    Abstract:

    AbstractThe silicon-based materials used for fabricating the Square Diaphragm for Micro-electro-mechanical systems capacitive transducer have inherent stress. This stress is known as residual stress. The presence of stress influences the mechanical behavior of the material, thereby influencing the performance characteristics of the devices. A methodology discussed earlier for modeling the small deflection of Square Diaphragm has been extended to take into account the effect of residual stress on the pull-in voltage and touch-point pressure. The results are compared with simulated and experimental ones.

  • A novel method to predict the effect of static charges on the pull-in voltage and touch-point pressure of the capacitive transducer with Square Diaphragm
    International Journal of Advances in Engineering Sciences and Applied Mathematics, 2010
    Co-Authors: Anurekha Sharma, P.j. George
    Abstract:

    Microelectromechanical systems (MEMS) use silicon based dielectric films such as SiO2 and Si3N4 for providing insulation. In capacitive transducers, these layers are used as insulation layers for capacitive actuators to prevent short-circuiting of electrodes by contact of electrodes and in case of touchmode capacitive pressure sensors (TMCPS), the dielectric layer provides for overload protection and provides for operation in the pressure ranges in which the Diaphragm comes in contact with dielectric. The pressure at which Diaphragm just touches the dielectric is referred to as touch-point pressure. In case of actuator, pull-in voltage is a critical parameter that decides the onset of instability in operation of the device. Silicon based dielectric thin films have the tendency to store or trap static charges, the presence of which alters the ideal behaviour of dielectrics. These trapped static charges introduced due fabrication processes; handling and operation affect the operation of capacitive transducers by influencing the pull-in voltage and by affecting the touch-point pressure. This paper presents a novel methodology, which predicts the pull-in voltage and touch-point pressure in presence of the static charges in a dielectric. The method proposed is less complex and less time consuming. Closed form expressions have been derived for pull-in voltage, touch-point pressure and critical displacement in presence of static charges. The results are compared with those obtained by experiment.

  • A simple method for calculation of the pull-in voltage and touch-point pressure for the small deflection of Square Diaphragm in MEMS
    Sensors and Actuators A-physical, 2008
    Co-Authors: Anurekha Sharma, P.j. George
    Abstract:

    There are a number of MEMS structures that make use of Diaphragms. The deformation of the Diaphragm for the purpose of actuation and transduction can be brought about by application of voltage and/or pressure or any other mechanical excitation like acceleration, force, etc. The amount of deformation can be measured by changes in the capacitance between the Diaphragm and the fixed electrode. The gap between the electrodes can be an air gap or can have an intervening layer of the dielectric on the fixed electrode along with the air gap. The pull-in voltage and touch-point pressure along with the structural and material properties are critical parameters that decide the behavior of the actuator/transducer. This paper presents a simple methodology, which is capable of representing small deflection of Diaphragm with pressure, and/or applied voltage. The method proposed is less complex and less time consuming in comparison with FEM tools. Closed form expressions have been derived for pull-in voltage with/without dielectric between the two electrodes and critical distance for pull-in. The closed form expressions for touch-point pressure have also been derived. The results are compared with those obtained by simulation as well as experiment.

Junbo Wang - One of the best experts on this subject based on the ideXlab platform.

  • A High-Q Resonant Pressure Microsensor with Through-Glass Electrical Interconnections Based on Wafer-Level MEMS Vacuum Packaging
    Sensors, 2014
    Co-Authors: Zhenyu Luo, Junbo Wang, Deyong Chen, Yinan Li, Jian Chen
    Abstract:

    This paper presents a high-Q resonant pressure microsensor with through-glass electrical interconnections based on wafer-level MEMS vacuum packaging. An approach to maintaining high-vacuum conditions by integrating the MEMS fabrication process with getter material preparation is presented in this paper. In this device, the pressure under measurement causes a deflection of a pressure-sensitive silicon Square Diaphragm, which is further translated to stress build up in “H” type doubly-clamped micro resonant beams, leading to a resonance frequency shift. The device geometries were optimized using FEM simulation and a 4-inch SOI wafer was used for device fabrication, which required only three photolithographic steps. In the device fabrication, a non-evaporable metal thin film as the getter material was sputtered on a Pyrex 7740 glass wafer, which was then anodically bonded to the patterned SOI wafer for vacuum packaging. Through-glass via holes predefined in the glass wafer functioned as the electrical interconnections between the patterned SOI wafer and the surrounding electrical components. Experimental results recorded that the Q-factor of the resonant beam was beyond 22,000, with a differential sensitivity of 89.86 Hz/kPa, a device resolution of 10 Pa and a nonlinearity of 0.02% F.S with the pressure varying from 50 kPa to 100 kPa. In addition, the temperature drift coefficient was less than −0.01% F.S/°C in the range of −40 °C to 70 °C, the long-term stability error was quantified as 0.01% F.S over a 5-month period and the accuracy of the microsensor was better than 0.01% F.S.

  • Resonant pressure sensor with through-glass electrical interconnect based on SOI wafer technology
    The 9th IEEE International Conference on Nano Micro Engineered and Molecular Systems (NEMS), 2014
    Co-Authors: Zhenyu Luo, Deyong Chen, Junbo Wang
    Abstract:

    This paper presents a resonant pressure sensor based on SOI wafer technology. In this device, pressure under measurement causes a deflection of a pressure-sensitive silicon Square Diaphragm, which is further translated to stress build up in “H” type doubly-clamped micro resonant beams, leading to resonant frequency shift. In device fabrication, through-glass vias and silicon-to-glass anodic bonding technologies were utilized. A high-strength hermetic sealing was then achieved after anodic bonding, with the resonators working in vacuum. Experimental results recorded a device resolution of 10pa, with the nonlinearity of 0.03% when pressure varying from 10kPa to 100kPa.

  • design and experiment of a laterally driven micromachined resonant pressure sensor for barometers
    Procedia Engineering, 2010
    Co-Authors: Deyong Chen, Meng Liu, Junbo Wang
    Abstract:

    Abstract A novel resonant pressure sensor based on electromagnetically driven and sensed H-type lateral beam resonators is described and FEA simulation is carried out on the analysis of the sensitivity, linearity and temperature drift of the pressure sensor. The resonant elements consist of four clamped-clamped boron diffused silicon beams (30 μm in thickness) organized along the diagonal direction suspended on a silicon Square Diaphragm, the differential output of two of which provides the sensor reading. The beams and the Diaphragm are fabricated by bulk micromachining techniques in one wafer, which is then bonded to another supporting silicon wafer in vacuum, leaving the resonant beams exposed to the pressure media. The cleaved sensor die is mounted to the metal package by fixing the die only at a corner through stacks of small silicon dies with epoxy. The proposed pressure sensor has advantages such as low cost, ease of fabrication and high performance, making it suitable for barometers.

Jian Chen - One of the best experts on this subject based on the ideXlab platform.

  • A High-Q Resonant Pressure Microsensor with Through-Glass Electrical Interconnections Based on Wafer-Level MEMS Vacuum Packaging
    Sensors, 2014
    Co-Authors: Zhenyu Luo, Junbo Wang, Deyong Chen, Yinan Li, Jian Chen
    Abstract:

    This paper presents a high-Q resonant pressure microsensor with through-glass electrical interconnections based on wafer-level MEMS vacuum packaging. An approach to maintaining high-vacuum conditions by integrating the MEMS fabrication process with getter material preparation is presented in this paper. In this device, the pressure under measurement causes a deflection of a pressure-sensitive silicon Square Diaphragm, which is further translated to stress build up in “H” type doubly-clamped micro resonant beams, leading to a resonance frequency shift. The device geometries were optimized using FEM simulation and a 4-inch SOI wafer was used for device fabrication, which required only three photolithographic steps. In the device fabrication, a non-evaporable metal thin film as the getter material was sputtered on a Pyrex 7740 glass wafer, which was then anodically bonded to the patterned SOI wafer for vacuum packaging. Through-glass via holes predefined in the glass wafer functioned as the electrical interconnections between the patterned SOI wafer and the surrounding electrical components. Experimental results recorded that the Q-factor of the resonant beam was beyond 22,000, with a differential sensitivity of 89.86 Hz/kPa, a device resolution of 10 Pa and a nonlinearity of 0.02% F.S with the pressure varying from 50 kPa to 100 kPa. In addition, the temperature drift coefficient was less than −0.01% F.S/°C in the range of −40 °C to 70 °C, the long-term stability error was quantified as 0.01% F.S over a 5-month period and the accuracy of the microsensor was better than 0.01% F.S.