共查询到20条相似文献,搜索用时 31 毫秒
1.
Microelectromechanical system (MEMS) based resonators can be used for filtering and frequency synthesis applications in many subcomponents of radio frequency wireless integrated circuits due to their small size, high level of frequency selectivity, low cost batch fabrication, ease of integration with CMOS circuits. Electroplated nickel is an attractive low cost material for CMOS compatible MEMS due to their low deposition temperatures. Among the different modes of vibration, radial-contour mode resonators are preferred for high frequency applications because they offer higher effective stiffness. Two different types of electroplated nickel based radial-contour bulk-mode circular disk resonator geometries which depend on capacitive actuation and readout technique is presented in this work. Material, mechanical and electrical characterizations were performed on these structures to show their functionality. 相似文献
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Huikai Xie Erdmann L. Xu Zhu Gabriel K.J. Fedder G.K. 《Journal of microelectromechanical systems》2002,11(2):93-101
Presents a new fabrication sequence for integrated-silicon microstructures designed and manufactured in a conventional complementary metal-oxide-semiconductor (CMOS) process. The sequence employs a post-CMOS deep silicon backside etch, which allows fabrication of high aspect ratio (25:1) and flat (greater than 10 mm radius of curvature) MEMS devices with integrated circuitry. A comb-drive resonator, a cantilever beam array and a z-axis accelerometer were fabricated using this process sequence. Electrical isolation of single-crystal silicon was realized by using the undercut of the reactive ion etch (RIE) process. Measured out-of-plane curling across a 120-μm-wide 25-μm-thick silicon released plate was 0.15 μm, which is about ten times smaller than curl of the identical design as a thin-film CMOS microstructure. The z-axis DRIE accelerometer structure is 0.4 mm by 0.5 mm in size and has a 25-μm-thick single-crystal silicon proof mass. The measured noise floor is 1 mG/√Hz, limited by electronic noise. A vertical electrostatic spring "hardening" effect was theoretically predicted and experimentally verified 相似文献
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Cheng K.M. Weng Z. Oliver D.R. Thomson D.J. Bridges G.E. 《Journal of microelectromechanical systems》2007,16(5):1054-1060
A noncontact electrostatic probing technique using a scanning probe microscopy cantilever is shown to actuate and detect the resonant behavior of a micromachined resonator. The method is capable of characterizing a resonator with resonant frequency much greater than that of the cantilever. The coupled oscillator model developed for this system describes the resonant response of the test resonator as detected through the probe, including the fourth-power dependence on the probe drive voltage. The veracity of this model is demonstrated through comparison with experimental data obtained from a test resonator with a resonant frequency ten times greater than the resonant frequency of the probe cantilever. This technique yields a straightforward determination of the resonant frequency and quality factor of a micromachined resonator, avoiding limitations due to optical interference and any reliance on a supporting circuitry. 相似文献
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《Journal of microelectromechanical systems》2009,18(1):103-110
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Hutomo Suryo Wasisto Qing Zhang Stephan Merzsch Andreas Waag Erwin Peiner 《Microsystem Technologies》2014,20(4-5):559-569
A closed-loop circuit is developed in this work for tracking the resonant frequency of silicon microcantilever mass sensors. The proposed closed-loop system is mainly based on a phase-locked loop (PLL) circuit. To lock onto the resonant frequency of the resonator, an actuation signal generated from a voltage-controlled oscillator is fed back to the input reference signal of the cantilever sensor. In addition to the PLL circuit, an instrumentation amplifier and an active low-pass filter are connected to the system for gaining the cantilever output signal and transforming a rectangular PLL output signal into a sinusoidal signal used for sensor actuation, respectively. To demonstrate the functionality of the system, a self-sensing silicon cantilever resonator with a built-in piezoresistive Wheatstone bridge is fabricated and integrated with the circuit. A piezoactuator is employed to actuate the cantilever into resonance. From the measurement results, the integrated closed-loop system is successfully employed to characterize a 9.4 kHz cantilever sensor under ambient temperature cross-sensitivity yielding a sensor temperature coefficient of ?32.8 ppm/°C. In addition to it, the sensor was also exposed to exhaled human breath condensates and e-cigarette aerosols to test the sensor sensitivity obtained from mass-loading effects. With a high frequency stability (i.e., a frequency deviation as low as 0.02 Hz), this developed system is intended to support the miniaturization of the instrumentation modules for cantilever-based nanoparticle detectors (CANTORs). 相似文献
7.
《Sensors and actuators. A, Physical》2007,133(1):64-71
This paper describes a novel single-layer bi-material cantilever microstructure without silicon (Si) substrate for focal plane array (FPA) application in uncooled optomechanical infrared imaging system (UOIIS). The UOIIS, responding to the radiate infrared (IR) source with spectral range from 8 to 14 μm, may receive an IR image through visible optical readout method. The temperature distribution of the IR source could be obtained by measuring the thermal–mechanical rotation angle distribution of every pixel in the cantilever array, which is consisted of two materials with mismatching thermal expansion coefficients. In order to obtain a high detection to the IR object, gold (Au) film is coated alternately on silicon nitride (SiNx) film in the flection beams of the cantilevers. And a thermal–mechanical model for such cantilever microstructure is proposed. The thermal and thermal–mechanical coupling field characteristics of the cantilever array structure are optimized through numerical analysis method and simulated by using the finite element simulation method. The thermal–mechanical rotation angle simulated and thermal–mechanical sensitivity tested in the experiment are 2.459 × 10−3 and 3.322 × 10−4 rad/K, respectively, generally in good agreement with what the thermal–mechanical model and numerical analysis forecast, which offers an effective reference for FPA structure parameters design in UOIIS. 相似文献
8.
Resonant Magnetic Field Sensor With Frequency Output 总被引:1,自引:0,他引:1
《Journal of microelectromechanical systems》2006,15(5):1098-1107
This paper presents a novel type of resonant magnetic field sensor exploiting the Lorentz force and providing a frequency output. The mechanical resonator, a cantilever structure, is embedded as the frequency-determining element in an electrical oscillator. By generating an electrical current proportional to the position of the cantilever, a Lorentz force acting like an additional equivalent spring is exerted on the cantilever in the presence of a magnetic field. Thus, the oscillation frequency of the system, which is a function of the resonator's equivalent spring constant, is modulated by the magnetic field to be measured. The resonant magnetic field sensor is fabricated using an industrial CMOS process, followed by a two-mask micromachining sequence to release the cantilever structure. The characterized devices show a sensitivity of 60 kHz/Tesla at their resonance frequency$f_0= 175~ kHz$ and a short-term frequency stability of 0.025 Hz, which corresponds to a resolution below 1$~mu T$ . The devices can thus be used for Earth magnetic field applications, such as an electronic compass. The novel resonant magnetic field sensor benefits from an efficient continuous offset cancellation technique, which consist in evaluating the frequency difference measured with and without excitation current as output signal. 1676 相似文献
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为提高生物微传感器的探测灵敏度,设计了一种低噪声的生物微传感器CMOS读出电路,提出了一种新型的相关双采样(CDS)电路.对读出电路的噪声进行抑制.在0.6μm CMOS工艺下,用Spectre仿真器对该电路进行了模拟,仿真结果表明,采用相关双采样的CMOS读出电路使传感器的输入输出转换具有良好的线性关系. 相似文献
11.
The smart integrated systems of tomorrow would demand a combination of micromechanical components and traditional electronics.
On-chip solutions will be the ultimate goal. One way of making such systems is to implement the mechanical parts in an ordinary
CMOS process. This procedure has been used to design an oscillator consisting of a resonating cantilever beam and a CMOS Pierce
feedback amplifier. The resonating frequency is changed if the beam is bent by external forces. The paper describes central
features of this procedure and highlights the design considerations for the CMOS-MEMS oscillator. The circuit is used as an
example of a “VLSI designer” way of making future integrated micromechanical and microelectronic systems on-chip. The possibility
for expansion to larger systems is reviewed. 相似文献
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A novel CMOS integrated Micro-Electro-Mechanical capacitive pressure sensor in SiGe MEMS (Silicon Germanium Micro-Electro-Mechanical System) process is designed and analyzed. Excellent mechanical stress–strain behavior of Polycrystalline Silicon Germanium (Poly-SiGe) is utilized effectively in this MEMS design to characterize the structure of the pressure sensor diaphragm element. The edge clamped elliptic structured diaphragm uses semi-major axis clamp springs to yield high sensitivity, wide dynamic range and good linearity. Integrated on-chip signal conditioning circuit in 0.18 μm TSMC CMOS process (forming the host substrate base for the SiGe MEMS) is also implemented to achieve a high overall gain of 102 dB for the MEMS sensor. A high sensitivity of 0.17 mV/hPa (@1.4 V supply), with a non linearity of around 1 % is achieved for the full scale range of applied pressure load. The diaphragm with a wide dynamic range of 100–1,000 hPa stacked on top of the CMOS circuitry, effectively reduces the combined sensor and conditioning implementation area of the intelligent sensor chip. 相似文献
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Integrated CMOS photodetectors and signal processing for very low-level chemical sensing with the bioluminescent bioreporter integrated circuit 总被引:3,自引:0,他引:3
Bolton EK Sayler GS Nivens DE Rochelle JM Ripp S Simpson ML 《Sensors and actuators. B, Chemical》2002,85(1-2):179-185
We report an integrated CMOS microluminometer optimized for the detection of low-level bioluminescence as part of the bioluminescent bioreporter integrated circuit (BBIC). This microluminometer improves on previous devices through careful management of the sub-femtoampere currents, both signal and leakage, that flow in the front-end processing circuitry. In particular, the photodiode is operated with a reverse bias of only a few mV, requiring special attention to the reset circuitry of the current-to-frequency converter (CFC) that forms the front-end circuit. We report a sub-femtoampere leakage current and a minimum detectable signal (MDS) of 0.15 fA (1510 s integration time) using a room temperature 1.47 mm2 CMOS photodiode. This microluminometer can detect luminescence from as few as 5000 fully induced Pseudomonas fluorescens 5RL bacterial cells. 相似文献
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提出一种新型基于微环谐振腔的集成光学加速度计,该加速度传感器具有较高的灵敏度(56.6 mV/gn)和良好的抗冲击性能(可达105gn)。介绍并分析了该加速度计的传感理论,建立了微环谐振腔耦合单元模型,通过Matlab软件和时域差分有限元(FDTD)法绘制了波导的模态传输曲线,优化了微环谐振腔的设计参数和微腔与波导的耦合间距,并且利用ANSYS给出了悬臂梁的承受冲击极限。最终,仿真结果与理论分析结果基本一致。该加速度计可为高灵敏抗冲击微光机电系统(MOEMS)传感器提供新思路和理论参考。 相似文献
16.
通过测量压电悬臂梁的等效电容来检测悬臂梁的振动信息,以应用于基于扫描探针技术的高密度信息存储中进行数据读取.在压电悬臂梁的PZT压电层上施加交流电场使其工作在共振状态,并使其自由端与存储介质进行周期性的接触.当悬臂梁的自由端扫描到数据点时,其自由端的振幅和所受到的外力将发生变化,进而引起PZT压电层的介电常数发生变化.因此,通过检测悬臂梁上压电层的等效电容变化,便可以得到悬臂梁的振幅改变量,从而实现了对存储介质上数据的读取.实验结果表明,该可以实现1nm的位移检测分辨率. 相似文献
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Resource-constrained networks such as deep space communications and mobile communications have the phenomena such us large-scale path loss,small-scale fading,and multipath effect,which are very hostile for information transmission.Combining Shannon’s source-channel coding theory with multidimensional modulation,an en/decoding method is proposed in this article called variable-length symbol-level joint sourcechannel and multidimensional modulation.Utilizing symbol-level source a priori information,an optimized symbol-level L-dimensional M-ary phase shift keying(LD-MPSK)constellation mapping function has been derived,which can increase free Euclidean distance between modulated symbols and enhance the decoding performance.It has been shown in the simulation results that the proposed scheme can achieve more than 2 dB signal-to-noise ratio gains compared with the conventional bit-level schemes under the condition of the same error rate. 相似文献
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CMOS Image Sensors have many applications currently. They are present everywhere and almost everyone owns many cameras based on these sensors ranging from mobile phones (with several cameras), to tablets, computers, security devices and cars. Although they work pretty well as we increase their resolution and quality we face a few problems. One of these problems is Flicker noise. The other source of noise, thermal, evolved a lot recently and flicker noise is now the main limitation regarding improving the performance. This work presents a new method to reduce the flicker noise contribution in the overall sensor noise by reducing the time for Double Sampling, allowing to filters more correctly the flicker noise spectrum introduced by the pixel source follower amplifier. We also introduce a way to remove the column induced lag that comes from the column readout circuitry by using strong and stable references. We propose a new amplifier that is used as a buffer for the reference voltage. At the same time Double Sampling is performed. This solution contributes both to reduce the current consumption and time between samples which also contributes to a lower power heat dissipation. The developed circuit can be seen as a generic solution for applications that need stable references and high resolution, resulting in a massively parallel circuit, as it is common in CMOS image sensors. The proposed solution is tested with a circuit containing 3000 readout columns. 相似文献
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《Journal of microelectromechanical systems》2009,18(3):671-678
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H. S. Wasisto S. Merzsch A. Waag I. Kirsch E. Uhde T. Salthammer E. Peiner 《Microsystem Technologies》2012,18(7-8):905-915
A novel MEMS-based cantilever sensor with slender geometry is designed and fabricated to be implemented for determining personal exposure to carbon engineered nanoparticles (NPs). The function principle of the sensor is detecting the cumulative mass of NPs deposited on the cantilever surface as a shift in its resonant frequency. A self-sensing method with an integrated full Wheatstone bridge on the cantilever as a piezoresistive strain gauge is introduced for signal readout replacing optical sensing method. For trapping NPs to the cantilever surface, an electrostatic field is used. The calculated equivalent mass-induced resonant frequency shift due to NPs sampling is measured to be 11.78?±?0.01?ng. The proposed sensor exhibits a mass sensitivity of 8.33?Hz/ng, a quality factor of 1,230.68?±?78.67, and a temperature coefficient of the resonant frequency (TC f ) of ?28.6?ppm/°C. These results and analysis indicate that miniaturized sensors based on self-sensing piezoresistive microcantilever can offer the performance to fulfill the requirements of real-time monitoring of NPs-exposed personnel. 相似文献