Mechanical stresses in thin films of copper on single-crystalline silicon

Kinetics of formation of mechanical stress, sigma(d), in thin Cu films on Si single-crystal substrate is investigated experimentally using the console method for various rates of deposition. Two-stage process of changes of the internal stresses, which reveal stretch behaviour, is observed. Mechanism of formation of grain boundaries is elucidated using the thermodynamical approach. Physical mechanism of formation of internal stresses inside the Cu condensates is proposed. Analytical relationship and criterial conditions for surface and interphase energies are obtained in order to describe the internal and external size effects in Cu films on Si single-crystal substrate. These are of Hall-Petch relation type.