The nanogap pirani - a pressure sensor with superior linearity in atmospheric pressure range

This paper reports a surface micromachined Pirani pressure sensor with superior linearity in atmospheric pressure range. The extremely narrow gap of the device (50 nm) increases the transition pressure of the device up to 300 kPa. When the heater power is kept constant, large change in the gap thermal conductivity at different pressures alters the heater temperature and introduces undesirable nonlinearity to the device output. We tested the device with constant heater temperature in order to eliminate the effect of the heater temperature variation. Testing the device with constant heater temperature, together with the high transition pressure of the device resulted in superior output linearity and significant sensitivity to absolute pressure from 101 kPa to 650 kPa.