Abstract: The invention relates to methods for the chemical application of coatings by the decay of gaseous compounds, in particular to methods for injecting gases into a reaction chamber. The invention also relates to means for feeding gases into a reaction chamber, said means providing for the regulation of streams of reactive gases, and ensures the possibility of obtaining multi-layer epitaxial structures having set parameters and based on nitrides of group III metals while simultaneously increasing the productivity and cost-effectiveness of the process of the epitaxial growth thereof. Before being fed into a reactor, all of the gas streams are sent to a mixing chamber connected to the reactor, and are then fed into the reactor via a flux former under laminar flow conditions. The mixing chamber and the flux former are equipped with means for maintaining a set temperature.