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Effect of Dielectric Charging on Capacitance Change of an SOI Based CMUT
摘要： Effect of dielectric charging on the performance of SOI based Capacitive Micromachined Ultrasonic Transducers (CMUT) has been investigated. Measurements on an SOI based CMUT show that that the capacitance change as a function of DC bias is considerably higher than analytically calculated values. Investigation shows that this deviation in capacitance from analytically calculated values is due to the combined effects of different dielectric charging phenomena due to a strong electric field, trap charges in the SOI oxide layer, the charge motion associated with the leakage current through the buried oxide layer, and the air in the CMUT cavity. Additionally, this charging effect degrades the transduction efficiency as the induced polarization reduced the effective bias across the CMUT. It is concluded that the buried oxide (BOX) layers in SOI wafers are not suitable for use as dielectric spacers in electrostatic MEMS devices.
关键词： SOI,dielectric charging,Capacitance,microfabrication,MEMS,CMUT,leakage current
更新于2025-11-14 17:28:48
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Design and Simulation of Novel Gated Integrator for the Heavy ion Beam Monitors System
摘要： In this study, the objective is to realize a Gated Integrator (GI) circuit for silicon strip, Si(Li), CdZnTe and CsI detectors etc. With the development of radioactive ion beam physics, heavy-charged particles like carbon ions have been applied to the treatment of deep-seated inoperable tumors in the therapy terminal of the Heavy ion Research Facility in Lanzhou (HIRFL) located at the Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS). A high resolution current measurement circuit was developed to monitor the beam current at 1pA range. The circuit consisted of a low current high sensitivity I/V converter and gated integrator in an energy spectroscopy. A low offset voltage precision amplifier and new guarding and shielding techniques were used in the I/V converter circuit which allowed to measure low current. This paper will show a MOS switch configuration which is used to prevent leakage current and novel technique to compensate a charge injection in the reset switch.
关键词： Noise,Gated Integrator,Energy Spectroscopy,Leakage Current Prevention,Charge Injection
更新于2025-09-23 15:23:52
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An Improved Proposed Single Phase Transformerless Inverter with Leakage Current Elimination and Reactive Power Capability for PV Systems Application
摘要： Single-phase transformerless inverters are broadly studied in literature for residential-scale PV applications due to their great advantages in reducing system weight, cost and elevating system efficiency. The design of transformerless inverters is based on the galvanic isolation method to eliminate the generation of leakage current. Unfortunately, the use of the galvanic isolation method alone cannot achieve constant common mode voltage (CMV). Therefore, a complete elimination of leakage current cannot be achieved. In addition, modulation techniques of single-phase transformerless inverters are designed for the application of the unity power factor. Indeed, next-generation PV systems are required to support reactive power to enable connectivity to the utility grid. In this paper, a proposed single-phase transformerless inverter is modified with the clamping method to achieve constant CMV during all inverter operating modes. Furthermore, the modulation technique is modified by creating a new current path in the negative power region. As a result, a bidirectional current path is created in the negative power region to achieve reactive power generation. The simulation results show that the CMV is completely clamped at half the DC link voltage and the leakage current is almost completely eliminated. Furthermore, a reactive power generation is achieved with the modified modulation techniques. Additionally, the total harmonic distortion (THD) of the grid current with the conventional and a modified modulation technique is analyzed. The efficiency of the system is enhanced by using wide-bandgap (WBG) switching devices such as SiC MOSFET. It is observed that the efficiency of the system decreased with reactive power generation due to the bidirectional current path, which leads to increasing conduction losses.
关键词： leakage current,transformerless inverter,reactive power,wide-bandgap (WBG),silicon carbide (SiC),photovoltaic (PV) power system
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE ISAF-FMA-AMF-AMEC-PFM Joint Conference (IFAAP) - Hiroshima (2018.5.27-2018.6.1)] 2018 IEEE ISAF-FMA-AMF-AMEC-PFM Joint Conference (IFAAP) - Control of Leakage Current through BaTiO<inf>3</inf> Film by Cumulative Cycle of Applied Voltage Scanning for ReRAM or Neuromorphic Application
摘要： We found a new phenomenon that shows a large change in leakage current through BaTiO3 (BTO) film with the maximum ratio of 107 to 109 observed in this work by changing cumulative cycle of voltage scan applied on the film capacitor. These leakage phenomena are thought to depend on several factors such as BTO film thickness, concentration of Vo+, bias voltage, its sweep rate and so on, because trapping/detrapping of carrier electron into/from oxygen vacancy would be a competition dependent on their rates and concentrations. These results imply that the leakage current can be controlled by some sequences or protocols of applied voltage scan, leading to use for ReRAM or neuromorphic applications.
关键词： ReRAM,leakage current,resistive switching,BaTiO3,oxygen vacancy
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 3rd International Conference on Signal and Image Processing (ICSIP) - Shenzhen, China (2018.7.13-2018.7.15)] 2018 IEEE 3rd International Conference on Signal and Image Processing (ICSIP) - A Two-frequency Subtraction Method to Improve Spectral Peak Identifications
摘要： We discuss a two-frequency subtraction technique to reduce the energy leakage in a Fourier spectrum. In our method, frequency components are determined by finding the periodogram over an interval such that the two frequencies will not interfere with each other. Such a method allows the subtraction of the two main frequency components more accurately from the original signal. The energy leakage from the main components is minimized to allow identification and more accurate determination of weaker components. Statistical error from the subtraction technique can be several times smaller than the FFT method. We show that the subtraction method is relatively robust for signals with varying amplitude or frequency.
关键词： time-frequency analysis,Fourier transform,spectrum estimation,spectral leakage
更新于2025-09-23 15:23:52
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A 600V PiN diode with partial recessed anode and double-side Schottky engineering for fast reverse recovery
摘要： In this paper, a novel 600V PiN diode for fast recovery is proposed and the operation mechanism as well as the high dynamic ruggedness of the device are analyzed in detail. The proposed structure features the alternating P/N region with partial recessed P region at anode side and the P- Schottky as well as the N Schottky contacts at both sides. In on-state, the carrier injection efficiency can be modulated by adjusting the work function of the anode P- Schottky contact (WSA), which is based on MSC (Metal-Semiconductor-Contacts) concept. As a result, the fast recovery is realized due to the reduced amount of the stored carriers and the shortened carrier extraction path. In off-state, the leakage current can be effectively suppressed attributed to the rapid pinch-off of the depletion layer. The forward voltage drop (VF) and the reverse recovery time (trr) of the proposed structure can be adjusted by changing the depth of the P- Schottky contact (tra) on the sidewall, without sacrificing the breakdown voltage (BV). The proposed structure achieves a trr of 75ns which is 45.7% and 33% lower than that of the conventional PiN and the MPS structure at the same VF of 0.965V, respectively. Moreover, the total amount of holes in the N buffer layer can be supplemented by adjusting the work function of the cathode N Schottky contact (WSC) during reverse recovery, resulting in a high-dynamic ruggedness with suppressed voltage oscillation and voltage overshoot.
关键词： Schottky contact,leakage current,dynamic characteristics,PiN diode,voltage overshoot,reverse recovery
更新于2025-09-23 15:23:52
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Switchable Schottky contacts: Simultaneously enhanced output current and reduced leakage current
摘要： Metal-semiconductor contacts are key components of nanoelectronics and atomic-scale integrated circuits. In these components Schottky diodes provide a low forward voltage and a very fast switching rate but suffer the drawback of a high reverse leakage current. Improvement of the reverse bias characteristics without degrading performance of the diode at positive voltages is deemed physically impossible for conventional silicon-based Schottky diodes. However, in this work we propose that this design challenge can be overcome in the organic-based diodes by utilizing reversible transitions between distinct adsorption states of organic molecules on metal surfaces. Motivated by previous experimental observations of controllable adsorption conformations of anthradithiophene on Cu(111), herein we use density functional theory simulations to demonstrate the distinct Schottky barrier heights of the two adsorption states. The higher Schottky barrier of the reverse bias induced by chemisorbed state results in low leakage current; while the lower barrier of the forward bias induced by physisorbed state yields a larger output current. The rectifying behaviors are further supported by nonequilibrium Green's function transport calculations.
关键词： van der Waals forces,Schottky contacts,Schottky barrier height,reverse leakage current,bistable state
更新于2025-09-23 15:23:52
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A thermo-sensitive fluorescent agent based method for excitation light leakage rejection for fluorescence molecular tomography
摘要： Fluorescence molecular tomography (FMT) is widely used in preclinical oncology research. FMT is the only imaging technique able to provide three-dimensional distribution of fluorescent probes within thick highly scattering media. However, its integration into clinical medicine has been hampered by its low spatial resolution caused by the undetermined and ill-posed nature of its reconstruction algorithm. Another major factor degrading the quality of FMT images is the large backscattered excitation light component leaking through the rejection filters and coinciding with the weak fluorescent signal arising from a low tissue fluorescence concentration. In this paper, we present a new method based on the use of a novel thermo-sensitive fluorescence probe. In fact, the excitation light leakage is accurately estimated from a set of measurements performed at different temperatures and then is corrected for in the tomographic data. The obtained results show a considerable improvement in both spatial resolution and quantitative accuracy of FMT images due to the proper correction of fluorescent signals.
关键词： Excitation Light Leakage,Biomedical Imaging,Fluorescence Molecular Tomography
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE International Conference on Electronics, Computing and Communication Technologies (CONECCT) - Bangalore (2018.3.16-2018.3.17)] 2018 IEEE International Conference on Electronics, Computing and Communication Technologies (CONECCT) - AlInN/GaN MIS-HEMTs with High Pressure Oxidized Aluminium as Gate Dielectric
摘要： AlInN/GaN metal insulator semiconductor high electron mobility transistor (MIS-HEMT) with high pressure oxidized aluminium as gate dielectric is investigated in this paper. The fabricated MIS-HEMT shows more than six orders of reduction in the gate leakage current in reverse bias and more than three orders of reduction in forward bias compared to the reference HEMT devices also fabricated on same substrates. A maximum drain current of 750 mA/mm was achieved due to improvement in the gate swing for MIS-HEMT. The MIS-HEMT devices also showed good improvement in the subthreshold slope and ID,ON/ID,OFF ratio compared to HEMT devices.
关键词： gate leakage current,MIS-HEMT,high pressure oxidation,AlInN/GaN,HEMT,Al2O3
更新于2025-09-23 15:23:52
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Leakage Mitigation in Heterodyne FMCW Radar for Small Drone Detection With Stationary Point Concentration Technique
摘要： To prevent potential hazards posed by fast-evolving drones, it is of importance to develop a radar system for drone detection. Frequency modulated continuous wave (FMCW) radars are widely used for that purpose. Heterodyne architectures are preferred for them to mitigate dc offset errors. Having said that, FMCW radars suffer from permanent leakage from the transmitter into the receiver. The leakage phase noise raises the total noise floor and limits the radar sensitivity. Here, we propose a stationary point concentration (SPC) technique in order to overcome the challenges. The SPC technique concentrates the leakage phase noise on a stationary point to alleviate the impact of the noise. The technique can be realized using digital signal processing without additional hardware. The results show that the proposed technique significantly lowers the noise floor.
关键词： heterodyne,down-conversion,leakage,digital signal processing (DSP),frequency modulated continuous wave (FMCW) radar,stationary point concentration (SPC) technique,stationary point,phase noise,noise floor
更新于2025-09-23 15:22:29