How to supply a CVD reactor with a steady-state mixture of two precursors vaporized from a single heated boat

The interest in CVD of two‐component and multicomponent layers is due to their application and advantage over the mono‐component ones established in various cases. The syntheses of new metal–organic compounds offer possibilities for such deposition. In the same time, the requirements to the exact dosage of the precursors also increase as to obtain a constant components ratio along the layers height. In some investigations, home‐made equipment for CVD is used wherein the precursors are vaporized in the carrier gas from their mixture in a single heated boat made of appropriate material. In the present report on the example of several two‐component mixtures of precursors, a theoretical analysis of the vapor–gas phase alterations due to the different precursor vapor pressures is demonstrated. The considerable changes shown indicate possibility for deposition of non‐homogeneous layers. To avoid this phenomenon, a change of the boat construction is suggested. It is based on an equation for the kinetics of vaporization from a flat surface into a flowing gas phase and a formula for the diffusivity coefficient in a binary gas mixture. The boat dimensions for the studied precursor mixtures are determined. An approach for experimental correction of the calculated boat construction is also suggested.