The role of the lattice step in epitaxial growth

Solid surfaces have many lattice steps. In epitaxy, aggregation of deposited atoms into islands or clusters during their diffusing can create many additional atomic steps. We study the effects of lattice steps on epitaxial growth in two aspects: 1. Movement of atoms across the step edge: a series of field ion microscope experiments reveal the importance of reflective and trapping properties of steps, and provide quantitative information that helps explain various growth modes observed in homoepitaxial growth. 2. Diffusion along the step edge: a number of field ion microscope experiments are done to determine diffusion parameters of a ledge atom along the step edge, and to derive the potential-energy diagram along different diffusion paths that helps explain the growth morphology. During growth, an atom undergoes a number of elementary atomic processes. Each process is characterized by a few energy parameters in bonding and diffusion. The integrated effect of all of these processes determines the growth process. We provide reliable experimental data and find the temperature ranges where various atomic processes are important.