CRITICAL THICKNESS OF EPITAXIAL GROWN SEMICONDUCTOR FILMS WITH STRAINED STRUCTURE

The critical thickness of structural transition from a tetragonal structure to a normal bulk structure for epitaxial ultrathin films deposited on the metallic and semiconductor substrates is thermodynamically considered. It is found that equilibrium between the elastic energy of the tetrahedral structure and the film–substrate interface energy is present when a critical thickness is reached. The predictions of the critical thickness are in agreement with the experimental results of films.