A novel high sensitive MEMS intraocular capacitive pressure sensor

This paper presents a novel high sensitive MEMS capacitive pressure sensor that can be used as a part of LC tank implant circuit for biomedical applications. The pressure sensor has been designed to measure pressures in the range of 0–60 mmHg that is in the range of intraocular pressure sensors. Intraocular pressure sensors are important in detection and treatment of an incurable disease called glaucoma. In this paper two methods are presented to improve the sensitivity of the capacitive pressure sensor. First low stress doped polysilicon material is used as a biocompatible material instead of p++silicon in previous work (Gu in Microfabrication of an intraocular pressure sensor, M.Sc Thesis, Michigan State University, Department of Electrical and Computer Engineering, 2005) and then some slots are added to the poly Si diaphragm. The novelty of this research relies on adding some slots on the sensor diaphragm to reduce the effect of residual stress and stiffness of diaphragm. The slotted diaphragm makes capacitive pressure sensor more sensitive that is more suitable for measuring intraocular pressure. The results yield a sensor sensitivity of 1.811 × 10^?5 for p++silicon clamped, 2.464 × 10^?5 1/Pa for polysilicon clamped and 1.13 × 10^?4 1/Pa for polysilicon slotted diaphragm. It can be seen that the sensitivity of the sensor with slotted poly Si diaphragm increased 6.2 times compared with previous work (clamped p++silicon diaphragm).     

Design and sensitivity analysis of capacitive MEMS pressure sensor for blood pressure measurement

Microsystem Technologies - This paper presents the design and simulation of a MEMS based clamped capacitive pressure sensor for blood pressure measurement. Normally, Blood pressure for human beings...     

CMOS integrated elliptic diaphragm capacitive pressure sensor in SiGe MEMS

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.     

A novel capacitive pressure sensor based on sandwich structures

This paper presents a sandwich structure for a capacitive pressure sensor. The sensor was fabricated by a simple three-mask process and sealed in vacuum by anodic bonding. The sensor, which utilizes a combined SiO/sub 2//Si/sub 3/N/sub 4/ layers as the elastic dielectric layers, exhibits high sensitivity. Mechanical characteristics of the sensor are theoretically analyzed based on a composite membrane theory and evaluated by use of finite element analysis (FEA). Square membrane sensors with side lengths of 800 /spl mu/m, 1000 /spl mu/m, 1200 /spl mu/m, and 1500 /spl mu/m were fabricated, providing a measured sensitivity of 0.08 pF/kPa, 0.12 pF/kPa, 0.15 pF/kPa, and 0.2 pF/kPa, respectively. The nonlinearity of the sensor is less than 1.2% over a dynamic range 80-106 kPa and the maximum hysteresis is about 3.3% to the full scale capacitance change. The TCO at 101 kPa is 1923 ppm//spl deg/C. All the electrodes of the sensor are leaded from the top side of the chip. Residual pressure in the sealed cavity at room temperature is evaluated by a pressure scanning test, indicating about 8 kPa. Comparison of experimental results with theoretical analysis shows that change of capacitance for the sandwich structure under pressure is mainly due to variation of the dielectric constant while geometric variations such as the area change of electrodes and the thickness change of dielectric layers is about two orders less than the variation of the dielectric constant. Sensitivity enhancements for the sensor are qualitatively discussed based on the physical effects of strained dielectrics, including electrostriction and flexoelectricity. [1551].     

一种新型电客式蓝宝石压力传感器

介绍一种高精密、高稳定、线性度佳、结构简单的新型电容式蓝宝石压力传感器.以圆形c面(0001)取向蓝宝石片作为压力传感器的膜片和基片,并且采用两种方案改善普通电容式蓝宝石压力传感器的非线性特性.第一种方法是在一个基片中央区电极内制作一个圆形无金属电极区(圆形无电极区的直径与中央区电极的直径具有特定比率),提高线性度,改...     

基于MEMS技术的微电容式加速度传感器的设计

给出了一种基于MEMS技术制作的微电容式加速度传感器的结构及工艺。为了准确地把握这种微电容式加速度传感器的力学和电学特性,仔细地建立了它的力学模型。在此基础上,详细分析了它的动态特性———模态。并用有限元的方法分析和计算了微电容式加速度传感器的加速度与电容信号的非线性输入输出关系,并结合实测参数验证了模型的有效性。最后提出了一种详细的有效的基于MEMS技术的微电容式加速度传感器的结构以及加工工艺流程。基于MEMS技术制作的微电容式加速度传感器具有结构简单、工作可靠和工作范围大的特点。根据这套方法,可以比较方便地设计并加工不同测量要求的加速度计。     

基于氧化铝陶瓷的电容式高温压力传感器

氧化铝陶瓷因其稳定的机械性能和高温鲁棒性得到了广泛的应用。文章以LC谐振电路为技术背景,提出了一种基于氧化铝陶瓷的电容式高温压力传感器,并通过厚膜集成工艺技术将一个定值电感与一个可变电容集成在氧化铝陶瓷基板上实现了传感器的制备。对传感器进行高温环境下的压力测试,实验结果表明:传感器能够完成600℃高温环境下1到5 bar范围内压力的原位测试,且在600℃高温环境下传感器的重复性误差,迟滞性误差和零点漂移分别为8.3%,5.05%和3.7%。     

电容式MEMS加速度传感器在气囊系统中的应用

安全气囊系统作为汽车被动安全的核心组成,有着极为重要的作用.为了提高其性能,设计了一种基于MEMS的外围加速度传感器的系统.该系统通过微机械结构检测汽车碰撞时的加速度,再通过一体式的专有集成电路对信号进行处理,然后将数据经总线传送到安全气囊控制器进行逻辑运算.通过实际碰撞测试,证明该设计系统能增强碰撞识别度和提早点火时间,极大地提高了安全气囊系统的性能.     

Development of a bioinspired MEMS based capacitive tactile sensor for a robotic finger

This paper presents the development of a MEMS based capacitive tactile sensor intended to be incorporated into a tactile array as the core element of a biomimetic fingerpad. The use of standard microfabrication technologies in realising the device allowed a cost efficient fabrication involving only a few process steps. A low noise readout electronics system was developed for measuring the sensor response. The performance of both bare and packaged sensors was evaluated by direct probing of individual capacitive sensor units and characterising their response to load–unload indentation cycles.     

A high sensitive MEMS capacitive fingerprint sensor using slotted membrane

In this paper a novel single-chip microelectromechanical systems (MEMS) capacitive fingerprint sensor with slotted membrane is developed to improve the sensitivity. The capacitive sensor consists of a thin, flexible membrane and a rigid back plate with air gap. In this study with making slots in upper electrode to decrease the mechanical stiffness of the membrane, using proportional T-shaped protrusion on diaphragm in order to concentrate the force from finger ridges, making holes in lower electrode to reduce the air damping and using low stress material for diaphragm, we have been succeeded to design a novel MEMS fingerprint sensor with high sensitivity compared with the previous works (Sato et al., IEEE Trans Electron Devices 52:1026–1032, 2005; Damghanian and Majlis, 2008 IEEE International Conference on Semiconductor Electronics (ICSE 2008), pp 634–638 2008). The behaviors of the fingerprint sensor with clamped and slotted membranes are analyzed using the finite element method (FEM). The results yield a sensitivity of 1.44 fF/Mpa for the clamped and 3.22 fF/Mpa for the slotted fingerprint sensor with a 50 × 50 μm² diaphragm. The sensitivity of the slotted structure is increased 2.236 times.     

Design and performance analysis of MEMS capacitive pressure sensor array for measurement of heart rate

Microsystem Technologies - In this paper, a diaphragm based MEMS capacitive pressure sensor array in conjunction with signal conditioning circuitry is designed for measuring Heart Rate (HR) of...     

A dual-axis MEMS capacitive inertial sensor with high-density proof mass

This paper reports a novel dual-axis microelectromechanical systems (MEMS) capacitive inertial sensor that utilizes multi-layered electroplated gold. All the MEMS structures are made by gold electroplating that is used as a post complementary metal-oxide semiconductor (CMOS) process. Due to the high density of gold, the Brownian noise on the proof mass becomes lower than those made of other materials such as silicon in the same size. The single gold proof mass works as a dual-axis sensing electrode by utilizing both out-of-plane (Z axis) and in-plane (X axis) motions; the proof mass has been designed to be 660 μm × 660 μm in area with the thickness of 12 μm, and the actual Brownian noise in the proof mass has been measured to be 1.2 \({\upmu}{\text{G/}}\sqrt {\text{Hz}}\) (in Z axis) and 0.29 \({\upmu}{\text{G/}}\sqrt {\text{Hz}}\) (in X axis) at room temperature, where 1 G = 9.8 m/s². The miniaturized dual-axis MEMS accelerometer can be implemented in integrated CMOS-MEMS accelerometers to detect a broad range of acceleration with sub-1G resolution on a single sensor chip.     

适用于电容式MEMS传感器的微小电容检测系统

针对电容式微机械陀螺测量困难的问题,设计了基于电容检测芯片AD7747和STM21F405单片机组合的微小电容检测系统。该系统主要包括I2C数据通信模块、串口通信模块、Flash存储模块以及单片机控制模块。最后通过实验来对其性能进行测试可得,该系统能够实现对微小电容的精确测量,分辨率可达1.6 fF,能够满足对电容式MEMS器件微弱信号的检测。     

基于支持向量机的电容式压力传感器建模方法

将支持向量机(SVM)引入传感器建模研究中,这里,SVM作为校正误差的一个逆模型.SVM有效地解决了小样本学习问题,因此,该方法对试验数据无特殊要求.最后,电容式压力传感器(CPS)建模试验结果证明了该方法的可行性和高效性.     

电容式MEMS超声传感器设计与分析

目前电容式MEMS超声传感器（CMUS）多为收发一体结构,但二种工作模式对传感器结构要求存在很大差异,设计时为了兼顾收发性能往往不能使传感器性能达到最优;此外,传统的电容式MEMS超声传感器还存在寄生电容大的缺点。针对以上问题,基于收发分离的思想,设计了一种专用作超声接收的MEMS电容式传感器,结构上采用上下电极引线互错,单元间电极联线交错的方式来减小寄生电容。通过理论分析和ANSYS仿真得到所设计传感器的最佳工作电压为586V,灵敏度为174.2fF/Pa,满足现有超声接收传感器的应用要求。     

基于MEMS实现SOI压力传感器工艺研究

应用压组效应原理制作硅氧化物绝缘体（SOI）压力传感器,具有耐高温、抗辐射、稳定性好等优点,本文说明了SOI在微电子机械系统（MEMS）技术上的实现优势,并对压力传感器SOI结构的实现工艺进行了探索性试验,完成了SOI压力传感器的设计和封装,在强调了压力传感器的测试方法的同时,对所设计的样品进行了测试。     

A novel capacitive pressure sensor and interface circuitry

A novel capacitive pressure sensor with the island-notch structure is introduced. Its theory model is established based on the structure theory of the plate capacitive pressure sensor. The relationships between the external pressure and capacitance of the capacitive pressure sensor with the island-notch structure are studied by using the method of the finite element analysis (FEA). The results show that the linearity of the capacitive pressure sensor with island-notch structure reached up 0.9941 in the linear measurement zone, the sensitivity reached up 0.0019 pF/kPa, and the measurement range of the capacitive pressure sensor is enlarged. Thus, the contradictory among measure sensitivity, linearity and measure range is effectively relieved in the capacitive pressure sensors with island-notch. In addition, the interface circuitry of the charge transfer is designed, and the performance of the interface circuitry is analyzed.     

基于SON构造的电容式绝对压力传感器设计

针对空洞层上硅工艺在制作高质量的单晶硅感压膜和真空密封腔上的优势,提出了将其应用于制作电容式绝对压力传感器。应用板壳理论建立了传感器压力检测的理论膜型,对传感器的感压膜进行理论计算和有限元仿真,并利用电容变化模型分析了传感器的灵敏度。给出了基于Pcap01芯片的微电容检测系统的设计,对于半径为100μm,厚度为1. 7μm的圆形感压膜,初始电容值为0. 278 p F,传感器灵敏度为0. 86 f F/k Pa。     

基于LTCC技术的电容式无源压力传感器制备

因陶瓷有稳定的电特性、机械鲁棒性和化学惰性而得到广泛的应用.为了实现高温、高压、潮湿等恶劣环境中的压力测试,以一种陶瓷和耐高温导电浆料为基质,采用低温共烧陶瓷(LTCC)工艺技术和非接触无线传输设计方法实现传感器的制备.传感器以LC谐振电路为基本工作原理,通过丝网印刷技术来实现电感、电容、导带等无源器件的安置,并且在空腔中填入碳膜(印刷碳浆料)有效地防止了层压中空腔的坍塌,所制传感器避免了器件的封装,引线外连,为传感器工作于高温、高压、潮湿等恶劣环境中奠定基础.