Measured Gas Concentrations and Flow Properties in SiH4–H2 Mixtures

Abstract

Each gas concentration in silane–hydrogen (SiH4–H2) gas mixtures was measured using a diaphragm gauge and a quartz friction pressure gauge (D- and Q-gauges). At constant pressures of 0.13–1.3 kPa, the Q-gauge pressure readings depended on the densities of SiH4 and H2. Therefore, the dependence of the Q-gauge pressure readings on the partial pressures of SiH4 could be used to measure the concentrations of these gases in the gas mixtures. The relative SiH4 density in the flow of gas mixtures was higher than the SiH4 flow rate ratio, indicating that the flow of the mixtures was intermediate between molecular and viscous. The viscosities of the gas mixtures estimated from the pressure-normalized Q-gauge pressures were compared with the calculations by Wilke's equation, with the finding that the viscosity of the gas mixture can be derived using the present measurement.