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A main problem associated with piezoresistive pressure sensors is the cross sensitivity sensed among different temperature. The influence of temperature is manifested as a change in the span and offset of the sensor output. In this paper, a new temperature compensation technique for a silicon pressure sensor is presented. We combine two sensors, the piezoresistive bridge and the compensation one, together to instead of the original single piezoresistive pressure sensor circuit. There are many advantages of using the configured double bridge technique, such as eliminates the zero pressure offset, compensates for the output variation, and gives the sensor extreme low drift of the temperature. Besides, it covers a wider temperature and pressure range, reduce the prime cost of sensors, and lessen the size of finished products. The simulation and experimental results are matched to our theoretical analysis. The feasibility of the new configure is proved.

In this paper we investigate the thermo mechanical behavior of a silicon piezoresistive pressure sensor. The totally built-in thin silicon membrane sensor response computation under constant and uniform pressure assuming small deflections have been determined using Finite Element Analysis (FEA) made in COMSOL. The model solved by COMSOL environment takes into account the entire sensor and thermal effects caused by the manufacturing process of the device. This allows a better understanding and monitoring the thermal drifts that can affect the sensor. COMSOL is easy to implement, ensures a good result in matters of affinity and it allows us to be closer to the real structure of the sensor with extreme flexibility. A temperature study of sensor was performed and the results allow us to predict the sensor behavior against temperature and to minimize this effect by optimizing the doping concentration. Finite Element Analysis (FEA) provides a reliable tool to carry out the required parametric studies in order to optimize the sensor performance.

AIMS—To demonstrate that a sensor, which is inserted through the sclera and placed in intimate contact with the choroid, can reliably detect changes in the intraocular pressure (IOP). METHODS—A manometer was used to control the IOP of three cadaver eyes in steps of 7 mm Hg. A piezoresistive pressure sensor was used to measure the pressure at the choroid through a 2.5 mm diameter hole that was surgically removed from the sclera. Data were collected for two configurations; with the sensor: (i) rigidly attached to a miniature positioning stage, and (ii) sutured to the sclera. RESULTS—Both configurations accurately tracked the manometer pressure from 10 mm Hg to 47 mm Hg. For the fixed sensor cases, the average difference between the pressure measured at the choroid and in the anterior chamber was 0.8 mm Hg for the three eyes. For the sutured sensor case, the average difference was 2.1 mm Hg—although a significant portion of this was attributed to an initial offset. The standard deviations at each pressure level for all of the choroid measurements were under 1.0 mm Hg. CONCLUSIONS—Small changes in IOP can be accurately measured by a sensor in contact with the surface of the choroid, for both a fixed sensor configuration and for a sensor sutured to the sclera. These results are the first step in the realisation of a surgically implantable microsensor to monitor IOP for patients suffering from low tension and other difficult to manage forms of glaucoma.

We report on a silicon microsurgical transducer that not only cuts tissue ultrasonically but also senses pressure and liquid flow rate during cutting. Horn-shaped silicon needles with integrated piezoresistive pressure sensors were fabricated using bulk micromachining technology. The needles were driven ultrasonically by bonded PZT-4 plates. The device can be driven at its longitudinal resonance to cut and sense pressure, while cut tissues are aspirated through the needle by an external pump. The integration of pressure sensor onto ultrasonic eye-surgery tool provides the potential of making phacoemulsification, the most popular cataract removal procedure, safer.

The experimental technique used for detection of subcooled boiling through analysis of the fluctuation contained in pressure transducer signals is presented. This work was partly conducted at the Institut fur Kerntechnik und zertorungsfreie Prufverfahren von Hannover (IKPH, Germany) in a thermal-hydraulic circuit with one electrically heated rod with annular geometry test section. Piezoresistive pressure sensors are used for onset of nucleate boiling (ONB) and onset of fully developed boiling (OFDB) detection using spectral analysis/ signal correlation techniques. Experimental results are interpreted by phenomenological analysis of these two points and compared with existing correlation. The results allow us to conclude that this technique is adequate for the detection and monitoring of the ONB and OFDB.

This paper presents the development of a single crystalline 3C-SiC piezoresistive pressure sensor using wafer bonding and bulk micromachining techniques. The wafer used to fabricate this pressure sensor consisted of a 3C-SiC/SiO2/Si structure that was obtained by wafer bonding and etchback. The pressure sensors were tested at temperatures up to 385°C and exhibited a sensitivity of 101.5 µV/V*psi at room temperature and 53.4 µV/V*psi at 385°C. The estimated gauge factor of the 3C-SiC piezoresistors is about −18.

Sensor systems based on CMOS technology benefit not only from the capability of silicon to realize both sensing and electronic functions, but also from the manufacturing maturity that CMOS technology has reached so far. In this contribution we discuss some of the important issues of CMOS sensor system design, such as available technologies and devices, design and implementation of sensor electronics, system design and verification, and also pay attention to testing, reliability and dependability. We present several examples of successfully integrated CMOS sensor systems, namely a 400 × 300 pixel image sensor, a magnetic-field sensor and a piezoresistive pressure sensor. All these sensors contain on-chip electronics and clearly demonstrate the advantages of monolithic integration. Finally, we discuss possible future developments in the area of CMOS sensor systems.

An interfacing circuit for piezoresistive pressure sensors based on CMOS current conveyors is presented. The main advantages of the proposed interfacing circuit include the use of a single piezoresistor, the capability of offset compensation, and a versatile current-mode configuration, with current output and current or voltage input. Experimental tests confirm linear relation of output voltage versus piezoresistance variation.

National Natural Science Foundation of China [51075344, 61274120, 51175444]; Fujian Province Major Projects on University-Industry Cooperation in Science and Technology [2013H6023]; Science and Technology Program of Xiamen [3502Z20123008, 3502Z20126006]

In the last years many micromachined sensors for measuring quite different quantities have been developed (e.g. [1][2]). The successful design of silicon micromachined sensors and their conversion into commercial products is still limited by the lack of full understanding of complex fault mechanisms. In order to detect those mechanisms it seems to be advantageous to investigate interrelated phenomena by different analysis methods. By combining results of several means the true nature of disturbing effects can be determined much more easily.This paper describes a comprehensive approach for investigating failure mechanisms in piezoresistive pressure sensors. Sophisticated methods of signal analysis were combined with special semiconductor techniques, determination of thermo-mechanical properties, Finite-Element- (FE-) simulation and Michelson interferometry. By that it was possible to separate disturbing mechanical as well as electrical effects and their relation to sensor output and sensor accuracy, respectively. In particular, we discovered complex influences of passivation layer systems (differing in geometrical and technological parameters) on sensor accuracy.

It is important to realize good consistency among different device units on a big wafer. The bad product consistency results from the processing deviation which is hard to control. A novel simulation method to control and reduce the influence of processing deviation on the sensitivity of a piezoresistive pressure sensor is provided in this paper. Based on finite element analysis (FEA) and mathematical integration, the performance of the pressure sensors is simulated. The pressure sensors are designed and fabricated according to the simulation results. The test results confirm that this simulation method can help to design the pressure sensor very precisely. From the simulation and test results, we find that properly enlarging the size of the square silicon membrane can improve the devices consistency.

This paper is devoted to an integrated piezoresistive pressure sensors based on novel concept of high-temperature microelectromechanical SOI sensors with a monolithic tensoframe. The SOI and integrated MEMS technologies are of especial interest for this sensors. The research enables main technology problems due to the features of a photolithography process on a relief surface with the high aspect ratio and resulted restrictions on the design parameters of SOI sensor three-dimensional micromechanical structures to be defined.

A novel design of piezoresistive, low pressure sensors is presented. This design exhibits a number of advantages compared to the conventional. The main objective of this development was realizing a sensor with high sensitivity, high pressure overload, and low nonlinearity. This paper describes the theory for the design of the piezoresistive low pressure sensor. Through the application of a square diaphragm bossed in the center, a piezoresistive low pressure sensor for the pressure range of ±10 kPa could be realized, exhibiting excellent sensitivity and low nonlinearity of 35 mV/V F.S.O. and 0,05 % respectively.

An interfacing circuit for piezoresistive pressure sensors based on a generalised current mode building block, termed operational floating amplifier (OFA), is presented. Main advantages of the proposed circuit are the very simple configuration using two OFAs and only one piezoresistor, and the highly linear frequency output, which is directly proportional to relative piezoresistance variation. Experimental results are included to demonstrate its performance.

The improvement of the base line stability of a silicon diaphragm piezoresistive pressure sensor is described. When a miniature pressure sensor mounted on a catheter tube is used for biomedical instrumentation, its surface is subject to ionic contamination, which causes electrical instabilities in the form of base line drift. The resistance modulation, which is attributed to the field effect of outer impurity ions, is proved experimentally to be the dominant mechanism of the drift. To eliminate the electrical drift, it is necessary to keep the resistance of piezoresistors constant, even if undesirable impurity ions exist. For this reason, a novel buried piezoresistor structure is proposed and studied experimentally. p + piezoresistors were formed on a thin n − diaphragm 10 μm thich and were then buried under an n + diffusion layer. This buried piezoresistor sensor gives an excellent stability (1.5 mmHg/day) in every atmosphere, including wet air.

This paper discusses selected problems related to silicon piezoresistive pressure sensor behavior which need consideration in order to maximize the potential sensor performance. A generic classification of sensor errors is introduced. Pressure non-linearity on voltage and current excitation modes and for both pressure directions is discussed. Temperature errors of four basic sensor characteristics are presented, including self-heating effects caused by excitation current or voltage change and warm-up time. Noise sources are discussed. Reported data represent the performance level achieved by a manufacturer and are believed to approach the limits now existing in low-cost pressure censor technology.

The usefulness of including polysilicon structures in solid-state sensors is discussed. A description of those electrical characteristics of LPCVD polysilicon layers that are most important with regard to sensor applications is followed by the presentation of some examples for polysilicon-based sensors, namely a high-temperature piezoresistive pressure sensor, a linear resistance temperature sensor and an interchangeable temperature-compensated pressure sensor.

An on-chip integrated piezoresistive pressure sensor with both voltage and frequency outputs has been developed. The sensor chip, having a size of 3 × 3.8 mm 2 , was realized by the use of a standard bipolar IC process. The output voltage span is 1 to 4 V for a pressure range of 0 to 750 mmHg. The pressure sensitivity of the voltage output is 4 mV/mmHg. The non-linearity is less than 0.4 % of the full scale. The sensitivity of the frequency output is about 30 kHz for a 750 mmHg change in pressure. The output is in the T 2 L level. The temperature coefficient of the sensitivity is less than 0.06%/°C in the temperature range −20 to 110 °C.

A thin-diaphragm piezoresistive pressure sensor for biomedical instrumentation has been developed using monolithic integratedcircuit (IC) techniques. The piezoresistive effect has been chosen for this device because it provides an observable resistance change that is a linear function of pressure and is observable at low stress levels. A diaphragm is used as a stress magnifying device; its magnification is proportional to the square of the ratio of the diaphragm diameter to its thickness. The pressure-induced stresses in the diaphragm are sensed by properly oriented piezoresistors interconnected to form a bridge.

Los sensores de presión piezorresistivos son ampliamente utilizados en aplicaciones de control y monitorización dentro del sector industrial. Estos sensores presentan problemas de dependencia térmica y no linealidades que afectan la exactitud de la medición. Por esta razón, es necesario utilizar circuitos de acondicionamiento de señales para obtener salidas de alta exactitud. Una de las técnicas más empleadas actualmente para acondicionar las señales provenientes de los sensores se basa en la utilización de procesadores digitales de señales y algoritmos de compensación. Este trabajo propone un nuevo algoritmo de calibración y compensación para sensores de presión piezorresistivos basado en la aproximación lineal por segmentos con compensación térmica. El algoritmo fue simulado empleando el software matemático MathCAD y utilizando datos de un sensor de presión piezorresistivo ficticio. El algoritmo fue validado experimentalmente implementándolo en 2 procesadores digitales de señales y utilizando sensores de presión manométricos ventilados de 10 bar en el intervalo de temperaturas de 0 a 80 °C. Se obtuvo como resultado que el máximo error a la salida del sensor, debido a la dependencia térmica del offset, fue de 0,081% del intervalo de medida. El error máximo obtenido a la salida provocado por la dependencia térmica de la sensibilidad fue de 0,106% del intervalo de medida. Se demostró la efectividad del algoritmo en la compensación térmica de los sensores de presión piezorresistivos. Este algoritmo puede ser aplicado a otros tipos de sensores que posean dependencias térmicas y que incorporen un microprocesador o un procesador digital de señales. The piezoresistive pressure sensors are widely used in monitoring and control applications within the industrial sector. These sensors have problems of temperature dependence, and non-linearities that affect the measurement accuracy. For this reason, it is necessary to use signal conditioning circuits for to obtain high accuracy outputs. One of the most common techniques currently used to conditioning the signals from the sensors is based on the use of digital signal processors and compensation algorithms. This paper proposes a new calibration and compensation algorithm for piezoresistive pressure sensors based on the linear segment approximation with thermal compensation. The algorithm was simulated using the mathematical software MathCAD and using data from a piezoresistive pressure dummy sensor. The algorithm has been validated experimentally implementing it into two digital signal processors using vented piezoresistives pressure sensors of 10 bar in the range of temperatures from 0 °C to 80 °C. The result was that the maximum error in the sensor output due to the temperature dependence of the offset was 0,081% of full scale output. The maximum error obtained at the output caused by the temperature dependence of the sensitivity was 0,106% of full scale output. The effectiveness of the algorithm is demonstrated in the thermal compensation of piezoresistive pressure sensors. This algorithm can be applied to other types of sensors having thermal dependencies and incorporating a microprocessor or digital signal processor.

Advancements in producing piezoresistive pressure sensors have opened up exciting new markets for these pressure determining devices. Up to 10 times more sensitive than the old transducers, and with response times as rapid as a millisecond, the new sensors are used in applications as diverse as automotive, hi‐fi, aerospace and medical equipment industries.

A silicon thin-diaphragm piezoresistive pressure sensor incorporating signal conditioning has been developed. The device exhibits 1% accuracy over a wide pressure range, requiring only two leads and no external components.

An extensive FEM analysis is presented on novel structures for miniature pressure sensors obtained by electrochemical etch stop on diffused membranes. The theoretical possibilities of each structure, in order to achieve the highest sensibility with the lowest nonlinearity, are considered on the basis of a new graphical method.

We attest the feasibility of a textile antenna in remote powering of a piezoresistive pressure sensor through inductive coupling for monitoring of intracranial pressure. The textile antenna made of metallized fabric on light-weight cell foam rubber substrate. Simulated and measured results of the wireless link performance along with measured output voltage versus pressure are presented.