Papers by Keyword: Electrostatic

Abstract: The general method to remove contaminated particles in the non-pattern cleaning such as pre-photo cleaning, post-deposition cleaning, and post-CMP cleaning is to physically remove particles using spray nozzle. However, high-speed fluids for increasing particle removal efficiency cause static electricity due to friction between liquid and nozzle surfaces, resulting in unexpected charge defects. In this study, we propose a method to reduce static electricity by changing the material of nozzle and grounding by visualizing static electricity according to electric voltage.

Abstract: This Paper presents the design and simulation of single walled carbon nanotube (SWCNT) based cantilever type electrostatic actuator using finite element analysis method (FEM). The pull-in voltage has been calculated for various chirality of the nanotube based cantilever beam actuators. The pull-in voltage are obtained for the various gap between electrode and ground of the cantilever beam through extensive simulations using ANSYS software. The results obtained shows that pull-in voltages varies from 2.5 to 13.5V with respect to nanotube chirality and gap length.

Abstract: Electrohydrodynamic (EHD) has been applied in many areas, such as EHD atomization, EHD enhanced heat transfer, EHD pump, electrospray nanotechnology, etc. EHD atomization is a promising materials deposition technique as it allows uniform and regular deposition, and offers a range of other advantages, such as low cost compared with other current techniques, easy set-up, high deposition rate, and ambient temperature. Simulation is carried out using ANSYS FLUENT system. The approach in this work was to simultaneously solve the coupled (EHD) and electrostatic equations. The fields of velocities and pressure, as well as electric characteristics of EHD flows, are calculated. The model does not include a droplet break-up model.

Abstract: Three main obstacles in modeling electrostatic torsional micromirror are hard to calculate – damping coefficient, mechanical spring constant and electrostatic torsion accurately. Because that parameter variations and model uncertainty of the torsional micromirror resulting from fabrication imperfections are inevitable, it is another problem to seek a control scheme for achieving accurate positioning and trajectory tracking of an electrostatic torsional micromirror. In this paper, aimed at a real prototype of circular electrostatic torsional micromirrorr, both static and dynamic behaviors are modeled and studied. A novel nonlinear Proportional, Integral and Derivative (PID) control are proposed in succession. Simulation results show that the system model derived is more accurate to the micromirror and the nonlinear PID can eliminate the static deviation.

Abstract: This paper presents the design considerations and the design procedure for low and medium power electrostatic energy harvester. First, the principle of electrostatic harvester is discussed then the design considerations are analyzed and assessed. Our assessments indicate that the electrostatic generator requires motion energy at low frequency to achieve higher power generation. This motion produces a higher power per unit volume in comparison to the vibration. The best material that can be used for the electrodes is silver as it has a higher conductivity, reliability, stability and it can handle high voltage up to 100 V when compared to the other common capacitor materials. The in-plane overlap realization method can be considered to be a suitable choice when applied to variable capacitor machine. With regard to the conditioning circuits, the switched capacitor regulator is the most appropriate option as it can solve the sizing problem and provides solution for the up or down conversion of voltage when comparing it with the other conditioning circuits. Finally, we propose a general electrostatic harvester design procedure according to the addressed designed considerations.

Abstract: In order to improve the ion transmission efficiency from atmospheric pressure MEMS electrospray (ESI) ion source to mass spectrometry (MS), a novel ion focusing device has been developed and simulated by FEM method (ANSYS). The ion focusing device consists of two electrodes with progressively smaller internal diameters to which electric potential are applied. Taguchi DOE has been used in the optimization process of the structures and critical dimensions for the device. Postprocessing has been implemented by Kriging interpolation method. The shapes of equipotential lines are measured to obtain the response for Taguchi DOE by CAD software. The significance of each factor and optimized structure has been obtained by signal-to-noise (S/N) ratio and means variance analysis. The simulation results will provide good reference for experiments.

Abstract: The fabrication of freestanding SiC microstructures on Silicon-On-Insulator (SOI) and semi-insulating Silicon substrates is reported. SiC layers were grown on SOI and semi-insulating Si by chemical vapour deposition (CVD) and to avoid the instability currently obtained in SOI structures, the growth process parameters have been optimized. Isotropic wet chemical etching of the Si sacrificial layer released the electrostatic SiC microstructures patterned by dry etching. Moreover a new concept for reducing the gap between resonators and electrodes by the uses of bistable mobile electrodes is introduced.

Abstract: The cuboid actuator is presented as a simple system for evaluation of the properties of dielectric elastomer actuators. The Ogden model as a component of this theory is evaluated and parameters for VHB 4910 found in literature are compared. The model is presented and evaluated with both intensive and extensive variables. For the first time direct effects of the width prestretch on electromechanical coupling are clearly presented. Also, the importance of choosing proper parameters for the hyper-elastic model is made clear via example.

Abstract: Silicon Carbide has proven its relevance for various MEMS and sensors devices applications. This paper presents the fabrication and the first test results of 3C-SiC electrostatic resonators actuated by applying a combination of AC and DC voltages. The recipe used for the fabrication has taken the advantage of the starting material, 3C-SiC grown on Si, which allows us to use the Si substrate as sacrificial layer to release the structures. Resonators have been fabricated by a two-step process, combining RIE ICP etching with HF wet etching. Resonators have been successfully electrostatically actuated in air-ambient condition. The resonance frequencies were clearly identified, although capacitive current created by actuation was not detected.