A variety of thin-film deposition techniques, including chemical vapor deposition (CVD) and atomic layer deposition (ALD), involve the use of liquid or solid precursors. The precursors used in both CVD and ALD processes frequently exhibit a low vapor pressure (e.g., less than 1 Torr at 25 C). The lack of high vapor pressure typically requires the use of a carrier gas to transport the precursor vapors from a delivery system to a deposition reactor. When using a carrier gas, it is a common misconception that precursor vaporization rate is governed solely by vapor pressure. Based on the kinetic theory of gases, precursor vaporization rate can be increased by using a carrier gas with higher diffusivity. For example, the vapors of a liquid or solid will reach 100% saturation (i.e., partial pressure equal to vapor pressure) faster in the presence of helium, compared to argon. This phenomenon can be exploited to increase the productivity of a film forming process by utilizing precursor/carrier gas mixtures with the maximum diffusivity, to reduce the time required to deposit a specified film thickness. To determine the effect of carrier gas diffusivity on precursor vaporization rate, experiments were performed using a flow-cell vaporizer. These experiments confirmed that the vaporization rate of tetradecane increased by greater than 50% using helium, compared to argon. In addition, experiments performed using naphthalene will also be presented. The naphthalene experiments provide useful insight into the vaporization behavior of solid precursors.