Semiconductor Pressure Sensor Research Articles

Аналитический метод определения концентрации легирующей примеси для снижения температурной погрешности полупроводникового тензодатчика давления

Аналитический метод определения концентрации легирующей примеси для снижения температурной погрешности полупроводникового тензодатчика давления

Special Issue on MEMS for Robotics and Mechatronics

MEMS (Micro Electro Mechanical Systems) is a technology that is used to incorporate sensors, actuators, microstructures, and circuits on chips by using a combination of various technologies with semiconductor process. MEMS are also used in robotics and mechatronics since they can provide compact, low-cost functional components that play crucial roles in their respective systems. We would like to elaborate on the history of MEMS technology, whose initial development started around 1970. In 1960s, Dr. Isemi Igarashi of Toyota Central R&D Labs., Inc. in Japan developed a semiconductor pressure sensor of piezo-resistance type. In 1980s, the pressure sensors were used to control automobile engines to clear exhaust gas regulations and thus contributed to solving environmental issues. In 1990s, semiconductor acceleration sensors were used for passive safety technologies to detect collision of automobiles and activate air bags, which resulted in decrease in traffic fatalities. In 2000s, an active safety system with gyro sensors was developed to detect and control spinning of a vehicle. In future, space recognition sensors with optical scanners to measure light propagation time and detect distance to an object will be used for autonomous driving. For smartphones, a microphone, an acceleration sensor, and a gyro sensor are used in user interface, and a film bulk acoustic wave resonator (FBAR) is used in a wireless communication filter. For projectors, the built-in circuit of a mirror array system is used to move mirrors placed in an array. After the development of projectors, films have not been used in movie theaters. MEMS are also widely used in medical and biological fields, such as blood pressure measurement. Esashi began research on a semiconductor ion sensor ISFET (ion sensitive field effect transistor) in 1971. ISFET detects ion concentration in electrolyte by exposing the insulating film of an insulated gate transistor to the liquid. He set up a prototyping facility when he was a graduate student and wrote only one paper on this research, although the prototyping facility was used afterwards. The ion sensor was certified under the Pharmaceutical Affairs Law after a 12-year application process and was used as catheter-type pH sensor to diagnose reflux esophagitis. MEMS are widely used for minimally invasive medical treatment, which causes minimum damage to human body. Moreover, MEMS are used as disposable sensors to prevent infection or as implanted devices. In addition, MEMS are used for production inspection and scientific instrument, including scanning probe microscopes (SPMs), which observe atoms using extremely small nano-probes, and probe cards that simultaneously test several integrated circuits on a wafer using aligned probes. When he was an associate professor, Esashi improved the prototyping facility that he made when he was a student and made a large scale integrated circuit (LSI). After he became a professor, he accepted researchers from more than 130 companies and developed MEMS using the prototyping facility to develop a product through the academia-industry collaboration. He realized integrated MEMS by combining LSI and MEMS. This includes a system of many tactile sensors attached on the body surface of a safe robot for real-time detection of contact through packet communication. After he retired from the university, he developed a “prototype coin laundry,” which enables companies to do develop without having their own prototyping facility. The prototype coin laundry is a system where engineers can use the prototyping facility to develop devices, and the system has been managed by successors. Unlike integrated circuits for which standardization is easy, standardization of MEMS is challenging because of difficulty in development. It is necessary to access various knowledge for the development of MEMS, and he has made efforts to provide the knowledge. Finally, we would like to thank authors who submitted papers to this Special Issue on MEMS for Robotics and Mechatronics as well as those who were involved in editing and reviewing the papers. We sincerely hope for further development in this field of research.

Highly-sensitive Hydrostatic Semiconductor Pressure Sensors

For the hydrostatic pressure calculation, we developed a semiconductor pressure sensor and analyzed the hydrostatic pressure sensitivities of silicon. In previous works, it exhibited a very low sensitivity. However, in this work, the sensitivity was improved drastically by combining p- type (in the nsubstrate) and n-type (in the p-well) resistor sensors with measuring the mid-point voltage of the combined sensor pair. Also, we could increase the sensitivity of hydrostatic pressure by controlling the voltage applied to the combined sensor pair. As an example, for the applied voltage of 20 V to the pair (compared to the previous works), the sensitivity was increased by up to 130 %.

DESIGN DIAMOND SEMICONDUCTOR PRESSURE TRANSDUCER

Pressure sensors play an important role in measuring variables in the control and automation systems of various processes. The purpose of this article is to study the design of a diamond semiconductor pressure sensor. In order to achieve this goal, the analysis was based on the Fourier law, but the authors made changes in the model of equations. The study was carried out using diamonds, as they are one of the promising materials for the manufacture of sensors and have high strength, thermal and radiation resistance. It was established that the output current in a semiconductor converter of the same load on the membrane does not depend on the supply voltage, which corresponds to the technical requirements developed in the converter. When determining the insulation resistance between the sensor plates, it was determined that the insulation resistance is less than 200 MW that meets the technical requirements.

Минимизация температурной составляющей погрешности и повышение чувствительности полупроводникового датчика давления

Минимизация температурной составляющей погрешности и повышение чувствительности полупроводникового датчика давления

Large Volume Intrathecal Bolus: CSF Pressure and Implications for Safety

ObjectivesLarge volume intrathecal (IT) bolus administrations yield an efficient method of therapeutic delivery to the cerebral CSF from a clinically accessible injection site. In non‐human primates, high volume bolus can translocate up to 90% of the administered substance to the cerebro‐cervical CSF immediately. It is known that administration of up to ca. 20% of the total CSF volume is safe for humans and monkeys; however, the safety parameters detailing the volume and underlying mechanistic limits have not been studied. The goal of the present work is to characterize the relationship between administered volumes and rates and intracranial pressure (ICP) as a safety parameter in rats and monkeys.MethodsICP was measured in the cisterna magna (rats) and the subcutaneous injection port leading to the lumbar CSF (monkeys) utilizing a 1F piezoresistive diffused semiconductor pressure sensor mounted at the tip of a 20 cm long 0.8 F polyimide catheter (Millar, Inc). Signal processing was carried out using a FE221 Bridge Amplifier coupled with a PowerLab 4/35 (ADInstruments). Control of both modules and waveform analysis was performed using LabChart 8 software (ADInstruments).ResultsICP in rats and monkeys was characterized by a periodic waveform of classical shape with spectrally resolved P1, P2, and P3 components (Fig. 1). Mean baseline ICP in rats was 9.3±2.3 mmHg. The adaptability of rats to varying ICPs was studied by plotting the time‐averaged amplitude of the P1 component against the mean ICP. Correlation between these two variables formed three distinctive zones: (1) low synchronization (good compensatory reserve) at low ICP, (2) good synchronization (poor compensatory reserve) at higher ICP, and (3) negative correlation (impaired compensatory mechanisms) at ICP > 32.3±6.5 mmHg (Fig. 1). The determined terminally “critical” ICP was then used to ascertain safe infusion rates and volumes in a separate group of rats. We found that infusion rates of up to 40 mkL/min could be used to safely administer volumes of at least 50% of CSF volume, whereas significantly smaller volumes could be infused at higher rates (Fig. 2). Our previous studies showed that monkeys tolerated bolus injections of 0.5 mL/kg body weight given at ca. 2 mL/min. Administration of this volume in a group of N=4 resulted in an ICP elevation by 47.5±5.9 mmHg. In rats and monkeys, the elevated post‐bolus ICP exponentially relaxed to the baseline within 11.3±8.1 min and 12.3±8.1 min, respectively.ConclusionsICP is a function of the rate and volume of fluid administration in the CSF and can safely be tolerated up to 32.3±6.5 mmHg (3.5‐fold) in rats. Comparable ICP relaxation times in monkeys and rats suggest similarities in the mechanisms of volume accommodation (hydrostatic compliance in the cervical region) and ICP adaptation (likely accelerated CSF drainage). The obtained data can improve the prediction of the safety of large‐volume IT drug administration and can be instrumental for identifying mechanisms regulating ICP adaptability.Support or Funding InformationThis study was supported by MGH ECOR Formulaic Award (2015) and NIH grants R01NS092838 and R21NS090049.

Theoretical relationship between p-type polysilicon thin film gauge factor and doping concentration

The polysilicon thin film piezoresistors are widely used in semiconductor pressure sensors. The polysilicon thin film has good piezoresistance properties, which are determined by the grain structure and doping concentration. The gauge factor of the polysilicon thin film is usually modified according to the relationship between gauge factor and doping concentration. The polysilicon thin films are classified into common polysilicon thin films and polysilicon nanofilms according to their thickness. The common polysilicon thin film thickness is more than 0.3 μm, which has good temperature characteristic, but its piezoresistance coefficient is small. However, the polysilicon nanofilm thickness is less than 0.1 μm, which has good temperature characteristic and high piezoresistance coefficient. The existing piezoresistance theory of the common polysilicon thin film cannot explain reasonably the experimental result of polysilicon nanofilm piezoresistance. Therefore, the tunneling piezoresistance model and an algorithm for the p-type polysilicon nanofilm piezoresistance coefficient were established in 2006. However, this algorithm presents an incomplete fundamental piezoresistance coefficient. In order to improve the polysilicon thin film piezoresistance theory, based on the tunneling piezoresistance model and the mechanism of silicon and the valence band hole conductivity mass with the change of stress, a novel algorithm for the piezoresistance coefficient of the p-type polysilicon thin film is presented. The theoretical formulas for three fundamental piezoresistance coefficients π11, π12 and π44 of the grain neutral and grain boundary regions, are presented respectively. With these formulas for the coefficients, the longitudinal and transverse piezoresistance coefficients for arbitrary crystal direction texture polysilicon can be obtained. According to the structure characteristics, the gauge factors of the p-type polysilicon nanofilm and the common polysilicon thin film are calculated, and then the longitudinal and transverse gauge factors are plotted each as a function of doping concentration, which are compared with the experimental results. According to the experimental results of the polysilicon nanofilm, the grain size is L=30 nm, the grain crystal directions are randomly distributed. The trap density in grain boundary region is Nt=1013 cm-2, the Young's modulus of elastic diaphragm is Y=1.69×1011 Pa, the Poisson ratio of elastic diaphragm is ν=0.062, the grain boundary width is δ=1 nm, and the thickness is 80 nm. The comparison indicates that the gauge factor average error between calculation and experiment is 0.5 times less than the average experimental difference between the maximum and the minimum for each doping concentration. For the common polysilicon thin film, according to the experimental results, its grain size L is 135 nm, thickness is 400 nm, the orientations of crystal grain neutral region are[311],[111] and[110] in the ratio of 49:31:20, i.e., 〈311〉:〈111〉:〈110〉=49:31:20, and the gauge factor calculated result is also good agreement with the experimental result. Therefore, the proposed algorithm is comprehensive and accurate, which is applicable to the p-type common polysilicon film and the polysilicon nanofilm.

Unsteady correlation between pressure and temperature field on impinging plate for dual underexpanded jets

In this paper, dual underexpanded impinging jets are experimentally studied by measuring unsteady wall static pressure and temperature fields using high response semiconductor pressure sensors and infrared imaging camera(100 captures per sec) with dual converging sonic nozzles. The flow field is also visualized by means of high speed schlieren system (up to 70000 frame per second) to clarify the unsteady behavior of the jet structures such as barrel shock wave, and Mach disk. Experiments were performed with a blow down tunnel changing the parameters such as the nozzle to plate distance, the distance between the two nozzles, and wind tunnel pressure ratio. The nozzle to plate distance L and the distance between the two nozzles H are non-dimensionalized by the nozzle diameter D covering H/D=1.5, 2.0, and 3, L/D= 2, 3, and 4, and po/pb=1.0 − 5.0, where po and pb are stagnation pressure and back pressure respectively. Although the response of the infrared camera is quite different from that of the high speed camera, the unsteady correlation between the pressure and temperature fields is confirmed under some conditions. Also the high speed schlieren pictures and the wall static pressure fluctuations suggest that the generation of the Mach disk promote the unsteady behavior of the jets. After the confirmation of the correlation, a simple way to find the severe fluctuating region can be provided according to the two dimensional unsteady temperature images without a lot of unsteady pressure measurements.

OS8-2-7 Analysis of flow fields in pressure hole for semiconductor pressure sensor

OS8-2-7 Analysis of flow fields in pressure hole for semiconductor pressure sensor

병렬구조의 압력측정 시스템 개발

In this paper, we developed a pressure measurement apparatus with the parallel structure to improve the measurement efficiency of pressure sensors by reducing the measurement time of pressure. The developed system has two parallel positions for loading Silicon pressure sensor and has a dual valve structure. The semiconductor pressure sensors prepared by Copal Electronics were used to confirm the performance of the developed measurement system. Two stage differential amplifier circuit was employed to amplify the weak output signal and the amplified output signal was improved utilizing a low-pass filter. New apparatus shows the measurement time of pressure two times shorter than that of conventional one with the serial structure, while both structures show the similar linear output versus pressure characteristics.

An Automatic Sorting System Based on Pneumatic Measurement

For reducing the machining difficulty and increasing the conjunction precision, an automatic sorting system is presented. The system combines the backpressure pneumatic measurement with a pneumatic-electric transfer technology. A semiconductor pressure sensor is used for the pneumatic-electric transfer. The air chamber pressure is converted to an electrical signal. The merits of the semiconductor pressure sensor include high conversion precision, high frequency response, and small volume. But it has a relatively big temperature drift if no compensation is provided. The sensor can compensate temperature drift. But the null shift and sensitivity shift still exist. Reducing supply voltage using an electric bridge or reducing supply current using a constant current source can reduce the shift. The null shift and sensitivity shift can be further reduced by auto-compensation using a calibrated gauge. The automatic sorting system can automatically sort injector valves and orifices quickly with a resolution of 0.2µm. The sorting accuracy is 0.5µm and the speed is approximately thirty pieces per minute. The system has the function of auto-control and error auto-compensation and has a high measuring efficiency and high precision.

Experimental studies and simulation for air flow on rotating drum in helical scan system

In this study, air pressures distribution around the rotating drum was measured using minute differential pressure meters that are composed of semiconductor pressure sensor and extended flexible probes. Computational simulation of the pressure and vortex inside and outside of the rotating drum was evaluated also, taking into account the effects of inner head mounting bases, holes and head mounting windows.

Numerical simulation and X-ray direct observation of mould filling during vacuum suction casting

The mould filling of the aluminium casting alloy AC4C was directly observed by X-ray radiography in order to evaluate the accuracy of simulated results for the mould filling behaviour of a vacuum suction casting process. A numerical method has been applied to simulate mould filling behaviour, in which evacuation of gas through the suction vent is taken into account and the backpressure of gas is coupled with the pressure field of the melt. Backpressure of gas in the empty mould cavity was also measured using a semiconductor pressure sensor. Experiments have been carried out at two different suction pressures (10 and 20 kPa) and three different decompression rates (1·2, 4·2 and 80 kPa s-1), controlled by the aperture of the valve between the gas pipe of the vacuum suction system. Experimental results showed that the effects of suction pressure and decompression rate on the mould filling behaviour were significant. The higher the suction pressure and decompression rate, the more turbulent the free surface of molten metal, resulting in earlier occurrence of gas entrapment, larger volumes of entrapped gas and higher risk of misrun. By comparing simulated results with experimental ones, it was found that good agreement could be obtained in terms of mould filling patterns, positions of gas entrapments and mould filling time. It was also found that results simulated by the conventional method, in which gas evacuation and the effects of backpressure on mould filling are not taken into account, showed poor agreement with experimental values.

커프 압력 조절에 따른 혈류량 변화 평가를 위한 임피던스법의 구현

In this study, we measured the blood flow on arm by non-invasive method and implemented a system to measure variation of the blood flow by estimating bio-electrical impedance and arterial pressure according to cuff pressure. The implemented system measured impedance variation according to pressure variation applied by artificial cuff pressure on the measuring position. The system consisted of pressure measuring part and impedance measuring part using 4-electrode method. Pressure measuring part was composed of semiconductor pressure sensor and electronic circuit for signal processing of sensor output signal. In addition, impedance measuring part was composed of constant current source circuit and lock-in amplifier for detecting impedance signal. We conducted experiments of impedance measuring part using standard resistance for performance evaluation of the implemented system. In addition we experimented to estimate variation of the blood flow by measuring impedances of the experimental group. We estimated ratio of the blood flow resistance using mean arterial pressure and variation of the blood flow. As a result the ratio of the blood flow resistance and variation of blood flow were in an inverse relationship with each other and the correlation coefficient was -0.96776.

Contact pressure measurement using silicon-based Al xGa 1− xAs semiconductor pressure sensors

Various types of pressure sensors are widely used in manufacturing, defence, medical and precision industries. Most of these sensors are based on either piezoelectric or piezoresistive mechanism for sensing applications. Piezoelectric pressure sensors are not suited for measuring static pressure mainly due to leakage of electric charges under constant pressure. Surface micromachined silicon pressure sensors, based on piezoresistive mechanism, are reliable with satisfactory pressure sensitivity. However, the use of mechanical diaphragm limits the performance of the sensor due to its slow response time when a pressure is applied. The measurable pressure by silicon pressure sensor is also low (mostly in kPa range) and is not suitable for high contact pressure measurement (MPa in range). This paper reports the fabrication and testing of pressure sensitive silicon-based Al x Ga 1− x As pressure sensors, which are suitable for both static and dynamic pressure measurements with a wide range of applied pressure. The pressure sensors are fabricated based on two different kinds of substrates, silicon and GaAs, and tested under various conditions. Contact pressure sensitivity, linearity, hydrostatic pressure sensitivity, hysteresis, temperature sensitivity and long-time stability (creep) test results for these two types of the fabricated pressure sensors have been compared and presented in this paper.

SENSORLESS ESTIMATION OF FLOW AND PRESSURE HEAD IN AN UNDULATION PUMP WITH PULSATILE DRIVEN

It is essential to measure pump flow and pressure to control the artificial heart. Although, the pump flow and pressure can be measured by electromagnetic flow sensor and semiconductor pressure sensor respectively, these methods have disadvantages due to its large size, poor stability, and anti-thrombogenicity. We have developed an undulation pump that can produce pulsatile flow by modulating its motor rotational speed. In our previous study, we have established a method to measure steady flow and pressure head, derived from the motor current and motor rotational speed. However, this method cannot be applied to pulsatile flow. In the present study, we developed a new method to measure pump flow and pressure head for pulsatile flow patterns. We have established an experimental formula in which the pressure head is derived from the angler speed and acceleration of the motor shaft, and motor current, pump flow be estimated from this pressure head and the motor rotational speed. The estimation pump flow and pressure head using this method, was compared with the actual value as measured by sensors. In an in vitro experiment, the mean error between this method and sensor were 0.23Umim for pump flow, 8.5mmHg for pressure head. In an in vivo experiment of total artificial heart in a goat, the mean error between these two methods were 0.87L/min for pump flow, 15.8mmHg for pressure head. These results show that this method has enough accuracy to measure the pump flow and pressure head for pulsatile flow.

International Standardization of Sensors and Micromachines

The importance and methodology of international standardization were introduced. The present situation of the specific standardization items such as semiconductor pressure sensors, Hall elements, semiconductor accelerometers, micromachine terminology, micromachine material evaluation methods were described.

SENSORLESS MEASUREMENT OF PULSATILE PUMP FLOW AND PRESSURE HEAD IN AN UNDULATION PUMP

It is essential to measure pump flow and pressure to control the artificial heart. Although, the pump flow and pressure can be measured by electromagnetic flow sensor and semiconductor pressure sensor, these methods have disadvantages as its size, stability, and anti-thrombogenisity. We have developed an undulation pump that can produce pulsatile flow by modulating its motor rotational speed. In our previous study, we have established a method to estimate steady flow and pressure head, derived from the motor current and motor rotational speed. However, this method cannot be applied to pulsatile flow. In the present study, we developed a new method to estimate pump flow and pressure head for pulsatile flow. We have established an experimental formula in which the pressure head is derived from the angler speed and acceleration of the motor shaft, and motor current. Pump flow can be estimated from this pressure head and the motor rotational speed. The estimation pump flow and pressure head using this method, were compared with the actual value as measured by sensors. In an in vitro experiment, the mean error between this method and sensor were 0.23L/mim for pump flow, 8.5mmHg for pressure head. In an in vivo experiment of total artificial heart in a goat, the mean error between these two methods were 0.87L/min for pump flow, 12.8mmHg for pressure head. These results show that this method has enough accuracy to estimate the pump flow and pressure head for pulsatile flow.

Application of pressure sensitive paint measurement to a low-solidity cascade diffuser of a transonic centrifugal compressor

A pressure sensitive paint (PSP) measurement has been known as a pressure field measurement technique based on the oxygen quenching phenomenon of luminescence of specific luminophores. A PSP measurement was applied for pressure field measurement in a low-solidity circular cascade diffuser of a single-stage transonic centrifugal compressor with 5 in pressure ratio for HFC134a gas. The oxygen concentration was about 500 ppm. Ru (bath-phen) was adsorbed on a silica-gel thin-layer chromatography sheet, and the sheet was pasted onto the side-wall between the cascade vanes. A drastic change in luminescent intensity was recognized during a surge condition. Also the pressure variations based on luminescent intensity agreed well with the pressure fluctuations measured using a semiconductor pressure sensor with high-frequency-response. It was shown that a PSP measurement worked well to investigate the unsteady pressure fields in a circular cascade diffuser of a transonic centrifugal compressor. Moreover, the time response of PSP becomes clear as a problem to be overcome for the present.

感圧塗料を用いた遷音速遠心圧縮機内圧力場の可視化

A pressure sensitive paint (PSP) measurement is recently known as a pressure field measurement technique based on oxygen quenching phenomenon of luminescence of specific luminophores. A PSP measurement was applied to a pressure field measurement in a low-solidity circular cascade diffuser of a single-stage transonic centrifugal compressor at 17, 800 rpm with 5 in pressure ratio for HFC134a gas. The oxygen concentration was about 500 ppm based on the measured velocity of sound of the gas. Ru (bath-phen) was used as a PSP. The PSP was adsorbed on a silica-gel thin-layer chromatography sheet, and the sheet was fixed on the side-wall between the cascade vanes. The luminescent intensity drastically changed during a surge condition. And the pressure variations based on luminescent intensity agreed well with the pressure fluctuations measured using semiconductor pressure sensors with high-frequencyresponse at three points. It was shown that a PSP measurement worked well to investigate unsteady pressure fields in a transonic centrifugal compressor. However, there are still some problems to be overcome.