Design and Fabrication of a High-Temperature SOI Pressure Sensor with Optimized Crossbeam Membrane

Abstract

This paper presents a SOI piezoresistive pressure sensor with the crossbeam membrane. The roots of the crossbeam were widened, which solved the problem of the poor dynamic performance of small-range pressure sensors working at a high temperature of 200 °C. A theoretical model was established to optimize the proposed structure, which combined the finite element and the curve fitting. Using the theoretical model, the structural dimensions were optimized to obtain the optimal sensitivity. During optimization, the sensor nonlinearity was also taken into consideration. The sensor chip was fabricated by MEMS bulk-micromachining technology, and Ti/Pt/Au metal leads were prepared to improve the sensor ability of high-temperature resistance over a long time. The sensor chip was packaged and tested, and the experimental results show the sensor achieved an accuracy of 0.241% FS, nonlinearity of 0.180% FS, hysteresis of 0.086% FS and repeatability of 0.137% FS at the high temperature. Given the good reliability and performance at the high temperature, the proposed sensor provides a suitable alternative for the measurement of pressure at high temperatures.

A Study on the Biofilm Removal Efficacy of a Bioelectric Toothbrush

“…The pressure sensor of the simulator was calibrated by applying various masses from 20 to 300 g. The result showed a standard correlation of the piezoelectric material (Figure 4). A piezoelectric pressure sensor can be calibrated using a power function [47]. A standard weight was applied to the pressure sensor and the output voltage was recorded (n = 3).…”

High-Precision Ultra-Long Air Slit Fabrication Based on MEMS Technology for Imaging Spectrometers

“…However, during the etching process, the bottom becomes irregular [22], as depicted in Figure 2, resulting in a non-uniform slit edge after etching through. As DRIE cannot etch SiO 2 , a buried oxide layer was used in the SOI sheet as the cutoff layer for DRIE etching [23], and the width of the bottom of the slit was controlled precisely by controlling the process parameters and over-etching both sides of the SOI sheet to ensure the edge quality. After completing the slit etching process, the SiO 2 at the bottom of the slit was removed through wet etching.…”

Structural Engineering in Piezoresistive Micropressure Sensors: A Focused Review

“…However, the balloon effect in the micropressure sensor cannot be easily treated using common diaphragm designs. For the flat diaphragm with a length L and thickness H, the sensitivity is directly proportional to the ratio (L/H), yet the nonlinearity of pressure-to-stress conversion is proportional to (L/H) 4 . This relationship means the nonlinearity has a faster increasing tendency when sensitivity is promoted, and there is an obvious constraint relationship between them [24].…”

“…Piezoresistive sensors, basing their operating principle on the piezoresistivity of functional materials, are one of the MEMS devices first to be developed and have revealed great capacity in detecting acceleration, pressure, force, fluid, sound, strain, stress, etc. [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. Piezoresistive micropressure sensors have great potential in many domains, such as tire pressure measurement systems for vehicles [ 10 ], biomedical catheters for healthcare [ 11 , 12 ], and pressure detectors for home appliances [ 13 ]; this can be attributed to their mature fabrication, structural simplicity, and excellent measuring performance [ 14 ].…”