MEMS capacitive pressure sensor monolithically integrated with CMOS readout circuit by using post CMOS processes

Abstract

In this paper, we presents a MEMS pressure sensor integrated with a readout circuit on a chip for an on-chip signal processing. The capacitive pressure sensor is formed on a CMOS chip by using a post-CMOS MEMS processes. The proposed device consists of a sensing capacitor that is square in shape, a reference capacitor and a readout circuitry based on a switched-capacitor scheme to detect capacitance change at various environmental pressures. The readout circuit was implemented by using a commercial 0.35 μm CMOS process with 2 polysilicon and 4 metal layers. Then, the pressure sensor was formed by wet etching of metal 2 layer through via hole structures. Experimental results show that the MEMS pressure sensor has a sensitivity of 11 mV/100 kPa at the pressure range of 100-400 kPa.

Wireless Battery-Free Harmonic Communication System for Pressure Sensing

“…The 3D printed pressure sensor eliminated the complex fabrication requirement in clean room, while providing similar capability such as piezo-based resistive sensors, MEMS-based capacitive sensor, or FBG-based pressure sensors [7][8][9][10]. The passive wireless feature successfully communicated the pressure information from pipe to interrogator, while eliminating the battery requirement and lowering down the maintenance cost [18].…”

“…A number of techniques have been proposed to monitor the pipeline pressure; such as piezo based resistive sensors, micro-electromechanical systems (MEMS)-based capacitive sensors, and fiber Bragg grating (FBG)-based negative pressure sensors [7][8][9][10]. The fabrication process of all the sensors is very complex, which either requires a hefty clean room process or very expensive tools for precision.…”

“…For example, the MEMS-based capacitive sensors require expensive substrate material, chemical etching, wire bonding, and separate housing [10]. Additive manufacturing is a viable alternative of this process, which has been previously proven for electronic system and component design [11].…”

Capacitance pressure sensor with S-type electrode for improved sensitivity

“…Kumar and Pant (2016) report an experimental study of two different pressure sensors with different configurations to study the characteristics such as sensitivity and non-linearity of the sensors. Jang and Yun (2017) report the fabrication of capacitive pressure sensor using complementary metal oxide semiconductor (CMOS) technology. The paper presents the detailed input-output analysis of the pressure sensor.…”

Resonant MEMS Pressure Sensor in 180 nm CMOS Technology Obtained by BEOL Isotropic Etching

“…Some of them are already integrated with readout electronics, or even with the processing electronics in the same die. For example, to cite a few of them, an integrated MEMS pressure sensor with a readout circuit for on-chip signal processing [ 1 ], Lorenz force based magnetometers [ 2 ], a micromachined acoustic sensor with integrated optical reading [ 3 ], monolithic metal oxide gas sensor microsystems [ 4 ], a digitally-controlled closed-loop MEMS gyroscope with sigma-delta force feedback [ 5 ] and high-quality integrated CMOS-MEMS resonators in [ 6 ]. Currently, some commercial CMOS-MEMS sensors are available: Single-die MEMS Oscillator [ 7 ] and a fully BiCMOS embedded RF-MEMS switch for 90–140 GHz applications.…”