Effect of temperature to characteristics of polysilicon based surface micromachining piezoresistive pressure sensor

This paper presents the effect of temperature to strain gauge resistance, sensitivity, and hysteresis of surface micromachining pressure sensor with polysilicon membrane and polysilicon resistor as piezoresistive strain gauge. The resistance value is nominally 2.7 k Omega, under normal atmospheric pressure and room temperature. The experiments measured the relationship between resistance of strain gauge and pressure under different temperatures setting. The pressure range was from 1 to 10 bar, whereas the temperature range was from -20 to 125degC. The resulting curves were used to calculate sensitivity, temperature hysteresis, pressure hysteresis, and temperature coefficient of resistivity (TCR). Increasing temperature resulted in higher resistance with TCR of 0.04%/degC. However, the sensitivity reduced at the rate of 0.165 and 0.144%/degC at pressure ranges of 1 -7 bars and 7 - 10 bars, respectively. Furthermore, pressure hysteresis also increased but stay within 5%, similar to temperature hysteresis value of 4.8%.