Langasite crystal microbalance frequency behavior over wide gas phase conditions for chemical vapor deposition

The frequency behavior of the langasite crystal microbalance (LCM) was studied, by measuring density and viscosity of gas mixtures consisting of inactive and reactive gases, such as nitrogen, hydrogen, trichlorosilane and monomethylsilane at atmospheric pressure in the temperature range from 160 to 600 °C. For expressing the LCM frequency decrease with the increasing concentrations of nitrogen, trichlorosilane and monomethylsilane gases in hydrogen, the measurement and the calculation of the LCM frequency difference between the gas mixture and the carrier gas were studied, as the practical method by optimizing the coefficients accounting for the gas properties. The obtained equation was shown to be applicable for a wide range of gas phase conditions in the chemical vapor deposition reactor.