Physical processes of the formation of structure and properties of films of transition-metal diborides

Physical processes are described that occur during the formation of the structure of film coatings of transition-metal diborides produced by the method of magnetron sputtering (in the DC and HF modes). The factors that affect the formation of the structure of the film coatings (energy of condensing atoms and substrate temperature) have been determined. The role of each factor in the formation of the film structure is shown. The optimum energy conditions for the formation of the transition-metal diboride films with the highest physicomechanical characteristics have been determined, i.e., the bias voltage equal to −50 V (DC regime) and ±50 V (HF regime); the substrate temperature ∼500°C. Under these conditions, there are formed hyperstoichiometric MB2.4 films with a grain size of ∼20 nm and greater. If the energy supplied to the growing film is insufficient in order to stimulate its crystallization and the formation of a (00.1) growth texture, hypostoichiometric nanostructured or amorphous (clusterized) films are formed. A physical model of the formation of critical nuclei leading to growth of a columnar structure in the films of transition-metal diborides is suggested.