Influence of the pressure range on temperature coefficient of resistivity (TCR) for polysilicon piezoresistive MEMS pressure sensor

Abstract

Sensitivity with respect to physical change of any type of sensor depends upon structure of the sensor and sensing material. If sensor is sensitive with more than single physical change (pressure or temperature etc) than sensitivity will get affected because of conflict in impact due to multiple physical parameters. Depending upon the designer’s intuition and experience, a variety of shapes of sensor had been proposed which can bear both the pressure and temperature. To understand the influence of temperature and pressure on the linearity and sensitivity, pressure sensors has been designed having 50 μm thick square diaphragm is being simulated and analyzed. The effect of pressure on Temperature Coefficient of Resistivity (TCR) of poly-silicon pressure sensor has been investigated in this paper. The stresses tempted in the piezoresistors and dislocation created in diaphragm have been studied using finite element method (FEM). The physical characteristics of sensor have been determined within the temperature range from 10 °C to 100 °C under the pressure range of 0 to 100 psi. It has been observed that TCR reduces with increasing pressure up to 30 psi, and beyond this pressure, the TCR begins to increase and thus the TCR shows the duality in nature. At 100 psi pressure, the calculated TCR for the diaphragm is found of the order of ∼7.7 × 10−3 (/°C). Thus, in conclusion, the pressure range ∼40–100 psi is recommended as the optimal range to achieve the better sensitivity. The temperature sensitivity of designed sensor has been found to be ∼0.10455 mV °C−1 while the pressure sensitivity of the proposed sensors which has been found to be 1.20051 mV psi−1. Hence, designed sensor can be used as both pressure and temperature sensing device incorporated into a single sensor.

MEMS-based Pt film temperature sensor chip on silicon substrate

“…Based on the data in figure 8, TCR, hysteresis and precision of temperature sensor chip are calculated and analyzed. The calculation of TCR is determined according to the following equation [27,28]:…”

Development of MEMS composite sensor with temperature compensation for tire pressure monitoring system

“…The performance of the temperature sensor is generally characterized by the temperature coefficient of resistance (TCR), sensitivity and measurement accuracy. The calculation formula of TCR is shown by [33,34]:…”

“…Generally, the circular and square shape membranes with fixed edges are used. Based on the small disturbance theory, the maximum mechanical stress σ max in the square and circular strained membrane are as follows [33,34]:…”

“…In theory, modeling and compensation for temperature drift of the pressure sensor could be carried out. According to formula (1), the influence of temperature on equivalent series resistance can be converted to the influence of temperature on initial resistivity, piezoresistive coefficient and stress [32][33][34]. On the one hand, the influence on initial resistivity and piezoresistive coefficient can be obtained based on empirical equation and experimental data [32,33].…”

Development of a Flexible Integrated Self-Calibrating MEMS Pressure Sensor Using a Liquid-to-Vapor Phase Change

“…Among the latest research works, many studies focused on enhancing sensitivity with different methods and materials [5][6][7][8]. Meanwhile, another popular topic is mitigating temperature dependence through circuit compensation and other approaches [9][10][11], which makes the in-situ calibration ideal for field monitoring applications.…”