ELASTICITY STUDIES OF THE CRITICAL THICKNESS OF AN EPILAYER DEPOSITED ON A COMPLIANT SUBSTRATE

摘要

The critical thickness of an epilayer on a compliant substrate with the semiconductor-on-insula- tor configuration is analytically investigated by isotropic elasticity using both superposition and Fourier transformation. The sliding boundary condition is adopted along the interface between the thin crystal sub- strate and the amorphous insulator layer where elastic constants differ from those of the crystal substrate. The critical thickness is determined from the zero formation energy of a misfit dislocation, i.e. the amount of reduced mismatch strain energy equaling the amount of created dislocation self energy. The results show that the critical thickness increases with decreases in the thickness of the thin crystal substrate and the elas- tic constant of the insulator. while Poisson's ratio has slight influences on the critical thickness.