Studies of the chemically stimulated thermal oxidation of GaAs and InP demonstrate that the physicochemical nature of the chemical stimulator determines the mechanism of the process and the possi bility of introducing it into the system in different ways. It has been shown that, when a chemical stimulator is introduced through the gas phase or applied to a semiconductor surface by mild methods, the oxidation process follows an oxygen transfer mechanism. When harsh methods are used to apply chemical stimulators that ensure persistent cyclic behavior of the process, it follows a synchronous catalytic mechanism.