NOVELTY - The method comprises maintaining the substrate in a reaction chamber (10) in motion, directing gaseous reactants within the chamber from a gas inlet in a downstream direction toward a surface of the substrate, selectively supplying energy at resonant frequency of the reactants in downstream of the inlet and in upstream of the substrate so as to impart sufficient energy to activate the reactants, and decomposing the reactants at the surface of the substrate. The gaseous reactants react with one another at the surface of the substrate so as to form a deposit on the substrate.    USE - The method is useful for depositing a compound semiconductor such as III-V semiconductors on a substrate such as a crystalline wafer for the production lasers, solar cells and indium gallium nitride and gallium nitride LEDs.    ADVANTAGE - The method allows uniform deposition of a compound semiconductor on a substrate, improves the decomposition at the surface of the substrate to provide greater radical N-containing species to form stoichiometric gallium nitride and to reduce the N-vacancies in the ultimate product, and prevents premature decomposition of the group V hydride compounds as they flow towards the substrate.    DETAILED DESCRIPTION - The method comprises maintaining the substrate in a reaction chamber (10) in motion, directing gaseous reactants within the chamber from a gas inlet in a downstream direction toward a surface of the substrate, selectively supplying energy at resonant frequency of the reactants in downstream of the inlet and in upstream of the substrate so as to impart sufficient energy to activate the reactants, and decomposing the reactants at the surface of the substrate. The gaseous reactants react with one another at the surface of the substrate so as to form a deposit on the substrate. The selectively supplied energy is microwave energy and infrared energy. One of the gaseous reactants is directed to a preselected area of the substrate, and energy is simultaneously selectively supplied to the preselected area of the substrate. The gaseous reactants remain separate from one another in a part of a flow region between the inlet and the surface of the substrate. The step of maintaining the substrate in motion includes rotating the substrate about an axis of rotation in the reaction chamber so that the gaseous reactants impinge on the surface of the substrate, which is parallel to the axis of rotation. The selectively applied energy is applied to the reactants at an angle of 90 degrees with respect to the axis of rotation. An INDEPENDENT CLAIM is included for a chemical vapor deposition reactor.    DESCRIPTION OF DRAWING(S) - The figure shows a side, elevational, partial and sectional view of a reactor.    Reaction chamber (10)    Spindle (12)    Spindle axis (14)    Rotary drive mechanism (16)    Reactant gas (30, 34)    Energy activator (31a)    Carrier gas. (32)