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.

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.

Pressure Sensing Using Electrostatic Capacitance

2006 ◽  
Vol 317-318 ◽  
pp. 865-868 ◽  
Author(s):  
Noriko Bamba ◽  
N. Endo ◽  
T. Takagi ◽  
Tatsuo Fukami
Keyword(s):  
Pressure Sensor ◽  
Static Pressure ◽  
Pressure Sensors ◽  
Ferroelectric Material ◽  
Pressure Sensitivity ◽  
Mechanical Pressure ◽  
Pressure Sensing ◽  
Sensor Performance ◽  
New Type ◽  
Mn Doped

Piezoelectric ceramic pressure sensors have been attracted great interest due to their simple and miniature structure compared with conventional sensors such as strain gauge sensor. A new type of static pressure sensor by using a change of permittivity upon applied mechanical pressure has been studied in this work. BaTiO3 ceramics with/without a small amount of Mn were used as sensing materials and the effect of poling treatment on their sensor performance was investigated. An anti-ferroelectric material, NaNbO3, was also examined. All materials could detect the change of pressure through the frequency shift of CR oscillator. Change of permittivity of non-doped BaTiO3 and Mn doped BaTiO3 without poling treatment were larger than that of PZT used as a reference, that is, BaTiO3 ceramics had higher-pressure sensitivity. BaTiO3 and relative materials, however, needed transit time to reach the steady state, while NaNbO3 was independent to the time. Conclusively, it seems that BaTiO3 and relative materials without poling treatment and the anti-ferroelectric material, NaNbO3, become possible candidates as a pressure sensor using permittivity change.

scholarly journals Design and simulation of a novel dual current mirror based CMOS‐MEMS integrated pressure sensor

2021 ◽  
Vol 15 (3) ◽  
pp. 268-278
Author(s):  
Shashi Kumar ◽  
Gaddiella Diengdoh Ropmay ◽  
Pradeep Kumar Rathore ◽  
Peesapati Rangababu ◽  
Jamil Akhtar
Keyword(s):  
Pressure Sensor ◽  
Current Mirror ◽  
Cmos Mems

Design and Analysis of Micro-Opto-Mechanical System Cantilever Integrated with Photonics Waveguide for Pressure Sensing Applications

2020 ◽  
Vol 18 (1) ◽  
pp. 18-25
Author(s):  
Veer Chandra ◽  
Rakesh Ranjan
Keyword(s):  
Light Intensity ◽  
Mechanical System ◽  
Pressure Sensor ◽  
Applied Pressure ◽  
Waveguide Structure ◽  
Slot Waveguide ◽  
Pressure Sensing ◽  
Sensing Applications ◽  
The Relationship ◽  
Slot Waveguides

In this work, the pressure sensing approach based on the Micro-Opto-Mechanical System (MOMS) cantilever integrated with waveguide structure has been explored. The MOMS based photonic sensors are drawing attention because of their high sensing capabilities. In the design of MOMS based cantilever pressure sensor, mainly two different waveguide structures, Rib and Slot waveguides have been considered. The deviation in light intensity at the output of the waveguide structure is mainly used to analyze the amount of exerted pressure at the free-end of cantilever. Using the different waveguide parameters such as, effective mode area, light intensity variations, etc., the performance comparison between Rib and Slot waveguides have been done. The relationship between the normalized light intensity at the waveguide output corresponding to the applied pressure has been established from the relationship between the deflection versus pressure and normalized intensity versus deflection. It has been anticipated that the performance of pressure sensor using Slot waveguide is significantly better than the Rib waveguide for some application.

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.

Development of circuit solution and design of capacitive pressure sensor array for applied robotics

2020 ◽  
Vol 8 (4) ◽  
pp. 296-307
Author(s):  
Konstantin Krestovnikov ◽  
Aleksei Erashov ◽  
Аleksandr Bykov
Keyword(s):  
Pressure Sensor ◽  
Output Signal ◽  
Sensor Array ◽  
Applied Pressure ◽  
Pressure Sensors ◽  
Fine Tuning ◽  
Capacitive Pressure Sensor ◽  
Cell Parameters ◽  
Linear Pattern ◽  
Sensor Structure

This paper presents development of pressure sensor array with capacitance-type unit sensors, with scalable number of cells. Different assemblies of unit pressure sensors and their arrays were considered, their characteristics and fabrication methods were investigated. The structure of primary pressure transducer (PPT) array was presented; its operating principle of array was illustrated, calculated reference ratios were derived. The interface circuit, allowing to transform the changes in the primary transducer capacitance into voltage level variations, was proposed. A prototype sensor was implemented; the dependency of output signal power from the applied force was empirically obtained. In the range under 30 N it exhibited a linear pattern. The sensitivity of the array cells to the applied pressure is in the range 134.56..160.35. The measured drift of the output signals from the array cells after 10,000 loading cycles was 1.39%. For developed prototype of the pressure sensor array, based on the experimental data, the average signal-to-noise ratio over the cells was calculated, and equaled 63.47 dB. The proposed prototype was fabricated of easily available materials. It is relatively inexpensive and requires no fine-tuning of each individual cell. Capacitance-type operation type, compared to piezoresistive one, ensures greater stability of the output signal. The scalability and adjustability of cell parameters are achieved with layered sensor structure. The pressure sensor array, presented in this paper, can be utilized in various robotic systems.

Micromachined Pressure Sensors on Optical Fiber Tip

2009 ◽  
Vol 74 ◽  
pp. 149-152
Author(s):  
X.M. Zhang ◽  
M. Yu ◽  
Silas Nesson ◽  
H. Bae ◽  
A. Christian ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Pressure Sensor ◽  
Linear Response ◽  
Applied Pressure ◽  
Pressure Sensors ◽  
Outer Diameter ◽  
Sensor Element ◽  
Batch Fabrication ◽  
In Vitro Measurements

This paper reports the development of a miniature pressure sensor on the optical fiber tip for in vitro measurements of rodent intradiscal pressure. The sensor element is biocompatible and can be fabricated by simple, batch-fabrication methods in a non-cleanroom environment with good device-to-device uniformity. The fabricated sensor element has an outer diameter of only 366 μm, which is small enough to be inserted into the rodent discs without disrupting the structure or altering the intradiscal pressures. In the calibration, the sensor element exhibits a linear response to the applied pressure over the range of 0 - 70 kPa, with a sensitivity of 0.0206 μm/kPa and a resolution of 0.17 kPa.

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