Fabrication and testing of PMOS current mirror-integrated MEMS pressure transducer

Sensor Review ◽  
2019 ◽  
Vol 40 (2) ◽  
pp. 141-151
Author(s):  
Shashi Kumar ◽  
Gaddiella Diengdoh Ropmay ◽  
Pradeep Kumar Rathore ◽  
Peesapati Rangababu ◽  
Jamil Akhtar
Keyword(s):  
Pressure Sensor ◽  
Pressure Transducer ◽  
Current Source ◽  
Experimental Result ◽  
Constant Current ◽  
Sensor Chip ◽  
Current Mirror ◽  
Pressure Sensing ◽  
Content Type ◽  
Input Pressure

Purpose This paper aims to describe the fabrication, packaging and testing of a resistive loaded p-channel metal-oxide-semiconductor field-effect transistor-based (MOSFET-based) current mirror-integrated pressure transducer. Design/methodology/approach Using the concept of piezoresistive effect in a MOSFET, three identical p-channel MOSFETs connected in current mirror configuration have been designed and fabricated using the standard polysilicon gate process and microelectromechanical system (MEMS) techniques for pressure sensing application. The channel length and width of the p-channel MOSFETs are 100 µm and 500 µm, respectively. The MOSFET M1 of the current mirror is the reference transistor that acts as the constant current source. MOSFETs M2 and M3 are the pressure-sensing transistors embedded on the diaphragm near the mid of fixed edge and at the center of the square diaphragm, respectively, to experience both the tensile and compressive stress developed due to externally applied input pressure. A flexible square diaphragm having a length of approximately 1,000 µm and thickness of 50 µm has been realized using deep-reactive ion etching of silicon on the backside of the wafer. Then, the fabricated sensor chip has been diced and mounted on a TO8 header for the testing with pressure. Findings The experimental result of the pressure sensor chip shows a sensitivity of approximately 0.2162 mV/psi (31.35 mV/MPa) for an input pressure of 0-100 psi. The output response shows a good linearity and very low-pressure hysteresis. In addition, the pressure-sensing structure has been simulated using the parameters of the fabricated pressure sensor and from the simulation result a pressure sensitivity of approximately 0.2283 mV/psi (33.11 mV/MPa) has been observed for input pressure ranging from 0 to 100 psi with a step size of 10 psi. The simulated and experimentally tested pressure sensitivities of the pressure sensor are in close agreement with each other. Originality/value This current mirror readout circuit-based MEMS pressure sensor is new and fully compatible to standard CMOS processes and has a promising application in the development CMOS-MEMS-integrated smart sensors.

Development of a current mirror-integrated pressure sensor using CMOS-MEMS cofabrication techniques

2018 ◽  
Vol 35 (4) ◽  
pp. 203-210 ◽  
Author(s):  
Shashi Kumar ◽  
Pradeep Kumar Rathore ◽  
Brishbhan Singh Panwar ◽  
Jamil Akhtar
Keyword(s):  
Pressure Sensor ◽  
Applied Pressure ◽  
Constant Current ◽  
Pressure Sensitivity ◽  
Current Mirror ◽  
Pressure Sensing ◽  
Content Type ◽  
Compressive Stresses ◽  
Cmos Mems ◽  
Mirror Configuration

Purpose This paper aims to describe the fabrication and characterization of current mirror-integrated microelectromechanical systems (MEMS)-based pressure sensor. Design/methodology/approach The integrated pressure-sensing structure consists of three identical 100-µm long and 500-µm wide n-channel MOSFETs connected in a resistive loaded current mirror configuration. The input transistor of the mirror acts as a constant current source MOSFET and the output transistors are the stress sensing MOSFETs embedded near the fixed edge and at the center of a square silicon diaphragm to sense tensile and compressive stresses, respectively, developed under applied pressure. The current mirror circuit was fabricated using standard polysilicon gate complementary metal oxide semiconductor (CMOS) technology on the front side of the silicon wafer and the flexible pressure sensing square silicon diaphragm, with a length of 1,050 µm and width of 88 µm, was formed by bulk micromachining process using tetramethylammonium hydroxide solution on the backside of the wafer. The pressure is monitored by the acquisition of drain voltages of the pressure sensing MOSFETs placed near the fixed edge and at the center of the diaphragm. Findings The current mirror-integrated pressure sensor was successfully fabricated and tested using in-house developed pressure measurement system. The pressure sensitivity of the tested sensor was found to be approximately 0.3 mV/psi (or 44.6 mV/MPa) for pressure range of 0 to 100 psi. In addition, the pressure sensor was also simulated using Intellisuite MEMS Software and simulated pressure sensitivity of the sensor was found to be approximately 53.6 mV/MPa. The simulated and measured pressure sensitivities of the pressure sensor are in close agreement. Originality/value The work reported in this paper validates the use of MOSFETs connected in current mirror configuration for the measurement of tensile and compressive stresses developed in a silicon diaphragm under applied pressure. This current mirror readout circuitry integrated with MEMS pressure-sensing structure is new and fully compatible to standard CMOS processes and has a promising application in the development CMOS-MEMS-integrated smart sensors.

A novel CMOS-MEMS integrated pressure sensing structure based on current mirror sensing technique

2015 ◽  
Vol 32 (2) ◽  
pp. 81-95 ◽  
Author(s):  
Pradeep Kumar Rathore ◽  
Brishbhan Singh Panwar ◽  
Jamil Akhtar
Keyword(s):  
Metal Oxide ◽  
Pressure Sensor ◽  
Wheatstone Bridge ◽  
Oxide Semiconductor ◽  
Current Mirror ◽  
Pressure Sensing ◽  
Content Type ◽  
Compressive Stresses ◽  
Cmos Mems ◽  
Bridge Circuits

Purpose – The present paper aims to propose a basic current mirror-sensing circuit as an alternative to the traditional Wheatstone bridge circuit for the design and development of high-sensitivity complementary metal oxide semiconductor (CMOS)–microelectromechanical systems (MEMS)-integrated pressure sensors. Design/methodology/approach – This paper investigates a novel current mirror-sensing-based CMOS–MEMS-integrated pressure-sensing structure based on the piezoresistive effect in metal oxide field effect transistor (MOSFET). A resistive loaded n-channel MOSFET-based current mirror pressure-sensing circuitry has been designed using 5-μm CMOS technology. The pressure-sensing structure consists of three identical 10-μm-long and 50-μm-wide n-channel MOSFETs connected in current mirror configuration, with its input transistor as a reference MOSFET and output transistors are the pressure-sensing MOSFETs embedded at the centre and near the fixed edge of a silicon diaphragm measuring 100 × 100 × 2.5 μm. This arrangement of MOSFETs enables the sensor to sense tensile and compressive stresses, developed in the diaphragm under externally applied pressure, with respect to the input reference transistor of the mirror circuit. An analytical model describing the complete behaviour of the integrated pressure sensor has been described. The simulation results of the pressure sensor show high pressure sensitivity and a good agreement with the theoretical model has been observed. A five mask level process flow for the fabrication of the current mirror-sensing-based pressure sensor has also been described. An n-channel MOSFET with aluminium gate was fabricated to verify the fabrication process and obtain its electrical characteristics using process and device simulation software. In addition, an aluminium gate metal-oxide semiconductor (MOS) capacitor was fabricated on a two-inch p-type silicon wafer and its CV characteristic curve was also measured experimentally. Finally, the paper presents a comparative study between the current mirror pressure-sensing circuit with the traditional Wheatstone bridge. Findings – The simulated sensitivities of the pressure-sensing MOSFETs of the current mirror-integrated pressure sensor have been found to be approximately 375 and 410 mV/MPa with respect to the reference transistor, and approximately 785 mV/MPa with respect to each other. The highest pressure sensitivities of a quarter, half and full Wheatstone bridge circuits were found to be approximately 183, 366 and 738 mV/MPa, respectively. These results clearly show that the current mirror pressure-sensing circuit is comparable and better than the traditional Wheatstone bridge circuits. Originality/value – The concept of using a basic current mirror circuit for sensing tensile and compressive stresses developed in micro-mechanical structures is new, fully compatible to standard CMOS processes and has a promising application in the development of miniaturized integrated micro-sensors and sensor arrays for automobile, medical and industrial applications.

CMOS-MEMS Based Current Mirror MOSFET Embedded Pressure Sensor for Healthcare and Biomedical Applications

2013 ◽  
Vol 647 ◽  
pp. 315-320 ◽  
Author(s):  
Pradeep Kumar Rathore ◽  
Brishbhan Singh Panwar
Keyword(s):  
Pressure Sensor ◽  
Biomedical Applications ◽  
Circuit Simulation ◽  
Applied Pressure ◽  
Pressure Sensors ◽  
Cmos Technology ◽  
Current Mirror ◽  
Sensing Element ◽  
Pressure Sensing ◽  
Cmos Mems

This paper reports on the design and optimization of current mirror MOSFET embedded pressure sensor. A current mirror circuit with an output current of 1 mA integrated with a pressure sensing n-channel MOSFET has been designed using standard 5 µm CMOS technology. The channel region of the pressure sensing MOSFET forms the flexible diaphragm as well as the strain sensing element. The piezoresistive effect in MOSFET has been exploited for the calculation of strain induced carrier mobility variation. The output transistor of the current mirror forms the active pressure sensing MOSFET which produces a change in its drain current as a result of altered channel mobility under externally applied pressure. COMSOL Multiphysics is utilized for the simulation of pressure sensing structure and Tspice is employed to evaluate the characteristics of the current mirror pressure sensing circuit. Simulation results show that the pressure sensor has a sensitivity of 10.01 mV/MPa. The sensing structure has been optimized through simulation for enhancing the sensor sensitivity to 276.65 mV/MPa. These CMOS-MEMS based pressure sensors integrated with signal processing circuitry on the same chip can be used for healthcare and biomedical applications.

Bossed diaphragm coupled fixed guided beam structure for MEMS based piezoresistive pressure sensor

Sensor Review ◽  
2019 ◽  
Vol 39 (4) ◽  
pp. 586-597 ◽  
Author(s):  
Manjunath Manuvinakurake ◽  
Uma Gandhi ◽  
Mangalanathan Umapathy ◽  
Manjunatha M. Nayak
Keyword(s):  
Pressure Sensor ◽  
Pressure Range ◽  
3D Structure ◽  
Maximum Strain ◽  
Sensing Element ◽  
Content Type ◽  
Good Linearity ◽  
Piezoresistive Pressure Sensor ◽  
Input Pressure ◽  
Geometrical Dimensions

Purpose Structures play a very important role in developing pressure sensors with good sensitivity and linearity, as they undergo deformation to the input pressure and function as the primary sensing element of the sensor. To achieve high sensitivity, thinner diaphragms are required; however, excessively thin diaphragms may induce large deflection and instability, leading to the unfavorable performances of a sensor in terms of linearity and repeatability. Thereby, importance is given to the development of innovative structures that offer good linearity and sensitivity. This paper aims to investigate the sensitivity of a bossed diaphragm coupled fixed guided beam three-dimensional (3D) structure for pressure sensor applications. Design/methodology/approach The proposed sensor comprises of mainly two sensing elements: the first being the 3D mechanical structure made of bulk silicon consisting of boss square diaphragm along with a fixed guided beam landing on to its center, forming the primary sensing element, and the diffused piezoresistors, which form the secondary sensing element, are embedded in the tensile and compression regions of the fixed guided beam. This micro mechanical 3 D structure is packaged for applying input pressure to the bottom of boss diaphragm. The sensor without pressure load has no deflection of the diaphragm; hence, no strain is observed on the fixed guided beam and also there is no change in the output voltage. When an input pressure P is applied through the pressure port, there is a deformation in the diaphragm causing a deflection, which displaces the mass and the fixed guided beam vertically, causing strain on the fixed guided beam, with tensile strain toward the guided end and compressive strain toward the fixed end of the close magnitudes. The geometrical dimensions of the structure, such as the diaphragm, boss and fixed guided beam, are optimized for linearity and maximum strain for an applied input pressure range of 0 to 10 bar. The structure is also analyzed analytically, numerically and experimentally, and the results are compared. Findings The structure offers equal magnitudes of tensile and compressive stresses on the surface of the fixed guided beam. It also offers good linearity and sensitivity. The analytical, simulation and experimental studies of this sensor are introduced and the results correlate with each other. Customized process steps are followed wherein two silicon-on-insulator (SOI) wafers are fusion bonded together, with SOI-1 wafer used to realize the diaphragm along with the boss and SOI-2 wafer to realize the fixed guided beam, leading to formation of a 3D structure. The geometrical dimensions of the structure, such as the diaphragm, boss and fixed guided beam, are optimized for linearity and maximum strain for an applied input pressure range of 0 to10 bar. Originality/value This paper presents a unique and compact 3D micro-mechanical structure pressure sensor with a rigid center square diaphragm (boss diaphragm) and a fixed guided beam landing at its center, with diffused piezoresistors embedded in the tensile and compression regions of the fixed guided beam. A total of six masks were involved to realize and fabricate the 3D structure and the sensor, which is presumed to be the first of its kind in the fabrication of MEMS-based piezoresistive pressure sensor.

A new method for the design of pressure sensor in hyperbaric environment

Sensor Review ◽  
2017 ◽  
Vol 37 (1) ◽  
pp. 110-116 ◽  
Author(s):  
Zhe Niu ◽  
Kui Liu ◽  
Hongbo Wang
Keyword(s):  
Pressure Sensor ◽  
Design Methodology ◽  
High Sensitivity ◽  
Measurement Range ◽  
New Method ◽  
Sensor Chip ◽  
Content Type ◽  
Hyperbaric Environment ◽  
Vital Parameters

Purpose The purpose of this paper is to introduce a new method for the design of a pressure sensor in the hyperbaric environment. Design/methodology/approach The new method focuses on two vital parameters that are closely related to the output and sensitivity of the sensor. The rectangular diaphragm structure is adopted, and the piezoresistors are planted on the surface accordingly. To verify the effect of the method, a contrastive sensor chip is fabricated in a conventional way, and two types of sensor chips are tested at the same time. Findings The new method for the design of a pressure sensor is advisable and favorable. The sensor fabricated by the method possesses outstanding high sensitivity and a wide measurement range. Originality/value This paper provides a new idea for increasing the measurement range of the pressure sensor with an acceptable sacrifice of sensitivity.

An Automatic Sorting System Based on Pneumatic Measurement

2005 ◽  
Vol 295-296 ◽  
pp. 563-568 ◽  
Author(s):  
Y.H. Wang ◽  
S.Q. Hu ◽  
Ying Hu
Keyword(s):  
Pressure Sensor ◽  
Supply Voltage ◽  
Current Source ◽  
Electrical Signal ◽  
Constant Current ◽  
Chamber Pressure ◽  
Temperature Drift ◽  
Constant Current Source ◽  
Automatic Sorting ◽  
Sorting System

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.

Design of biomimetic human-skin-like tactile flexible sensor

Sensor Review ◽  
2019 ◽  
Vol 39 (3) ◽  
pp. 397-406
Author(s):  
Xiaozhou Lu ◽  
Xi Xie ◽  
Qiaobo Gao ◽  
Hanlun Hu ◽  
Jiayi Yang ◽  
...  
Keyword(s):  
Human Skin ◽  
Pressure Sensor ◽  
Material Selection ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Structure Design ◽  
Design Parameters ◽  
Lower Electrode ◽  
Pressure Sensing ◽  
Content Type

Purpose The hands of intelligent robots perceive external stimuli and respond effectively according to tactile or pressure sensors. However, the traditional tactile and pressure sensors cannot perform human-skin-like intelligent properties of high sensitivity, large measurement range, multi-function and flexibility simultaneously. The purpose of this paper is to present a flexible tactile-pressure sensor based on hyper-elastics polydimethylsiloxane and plate capacitance. Design/methodology/approach With regard to this problem, this paper presents a flexible tactile-pressure sensor based on hyper-elastics PDMS and plate capacitance. The sensor has a size of 10 mm × 10 mm × 1.3 mm and is composed of four upper electrodes, one middle driving electrode and one lower electrode. The authors first analyzed the structure and the tactile-pressure sensing principle of human skin to obtain the design parameters of the sensor. Then they presented the working principle, material selection and mechanical structure design and fabrication process of the sensor. The authors also fabricated several sample devices of the sensor and carried out experiments to establish the relationship between the sensor output and the pressure. Findings The results show that the tactile part of the sensor can measure a range of 0.05-1N/mm2 micro pressure with a sensitivity of 2.93 per cent/N and a linearity of 0.03 per cent. The pressure part of the sensor can measure a range of 1-30N/mm2 pressure with a sensitivity of 0.08 per cent/N and a linearity of 0.07 per cent. Originality/value This paper analyzes the tactile and pressure sensing principles of human skin and develop an intelligent sensitive human-skin-like tactile-pressure sensor for intelligent robot perception systems. The sensor can achieve to imitate the tactile and pressure function simultaneously with a measurement resolution of 0.01 N and a spatial resolution of 2 mm.

Design and Application of the Testing System for a New Pipe Pressure Sensor

2014 ◽  
Vol 904 ◽  
pp. 395-398
Author(s):  
Xiao Ming Zhang ◽  
Yi Yuan ◽  
Jian Min Liu
Keyword(s):  
Data Acquisition ◽  
Pressure Sensor ◽  
Dynamic Pressure ◽  
Current Source ◽  
Test System ◽  
Constant Current ◽  
Measured Signal ◽  
Constant Current Source ◽  
Pass Filter ◽  
Low Pass Filter

The new pipe pressure sensor is a clamp-on ICP (Integrated Circuit Piezoelectric) type dynamic pressure sensor, mainly for the clamp-on pressure testing of high pressure fuel pipe. In testing, the vibration of the fuel injection pumps and diesel engine will disturb the clamp-on pressure signals, resulting in one of the measured signal to noise ratio is low, the second is the test system, in particular the signal transmission have a significant impact. In response to these problems, designed a PCI data acquisition card building-in constant-current source and special low pass filter, and developed the corresponding data acquisition software based on C++ Builder. The bench and real vehicle testing show: the test system can better fit with the new type pressure sensor to obtain accurate clamp-on pressure signals.

Current-source 1-Ph inverter design for aircraft applications

2020 ◽  
Vol 92 (8) ◽  
pp. 1295-1305
Author(s):  
Eralp Sener ◽  
Gurhan Ertasgin
Keyword(s):  
Pulse Width Modulation ◽  
High Efficiency ◽  
Current Source ◽  
Sine Wave ◽  
Constant Current ◽  
Constant Current Source ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Content Type ◽  
Loop Control

Purpose This paper aims to present an inverter with a current-source input for 400 Hz avionic systems to have a system which removes DC-link capacitors and presents a high efficiency. Design/methodology/approach A battery-powered DC link inductor generates a constant-current source. A single high-frequency switch is used to provide a sinusoidally modulated current before the inverter. The output of the switch is “unfolded” by a thyristor-based H-bridge inverter to generate an AC output current. The system uses a CL low-pass filter to obtain a 400 Hz pure sine wave by removing pulse width modulation components. Findings Simulations and Typhoon HIL real-time experiments were performed with closed-loop control to validate the proposed inverter concept while meeting the critical standards of MIL-STD-704F. Originality/value This current source inverter topology is suitable for avionic systems that require 400 Hz output frequency. The topology uses small DC-link inductor and eliminates bulky capacitor which determines the inverter lifetime.

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