Anisotropic unstable and stable growth of homoepitaxial (1 0 0) InP films

An extended study on the dynamics of growth of homoepitaxial InP films by chemical beam epitaxy is presented. Different morphologies (from layered to mounded) were achieved by changing growth temperature. In particular, ripples were observed at an intermediary temperature value. Their shape and evolution depend on both the direction and miscut angle of substrates used. Time and scale behavior of roughness and height-difference correlation functions calculated from atomic force microscopy data show that the average mound size increases during growth while the ripple wavelength remains approximately constant. Once ripples are present on the surface, growth becomes more stable due to surface faceting. Our experimental and simulation results indicate that competition between diffusion with anisotropic spatial bias and faceting play an important role in the growth process, giving rise to several different law regimes. When the film morphology is mounded, however, no stable temporal law regime is observed although a roughness exponent can still be measured, as expected for unstable growth with spatial diffusion bias.