A Pirani pressure sensor is based on the fact that the thermal conductivity of a gas is dependent on the pressure. The structure presented in this paper consists of a heated microbeam, which is placed above a v-groove in a heat sink. The temperature distribution along the microbeam is a measure for the thermal conductivity of the surrounding gas. Measuring the temperature distribution instead of the average temperature of the beam has two advantages: the measurement becomes independent of the Temperature Coefficient of Resistance of the temperature sensing resistors and the heat loss to the substrate is implicitly taken in account, which extends the lower pressure range.
展开▼
