A SIMPLE-MODEL OF EPITAXIAL-GROWTH

A discrete solid-on-solid model of epitaxial growth is introduced whic h, in a simple manner, takes into account the effect of an Ehrlich-Sch woebel barrier at step edges as well as the local relaxation of incomi ng particles. Furthermore, a fast step edge diffusion is included in 2 + 1 dimensions. The model exhibits the formation of pyramid-like stru ctures with a well-defined constant inclination angle. Two regimes can be clearly distinguished: in an initial phase (I) a definite slope is selected while the number of pyramids remains unchanged. Then a coars ening process (II) is observed which decreases the number of islands a ccording to a power law in time. Simulations support self-affine scali ng of the growing surface in both regimes. The roughness exponent is a lpha = 1 in all cases. For growth in 1 + 1 dimensions are obtain dynam ic exponents z = 2 (I) and z = 3 (II). Simulations for d = 2 seem to b e consistent with z = 2 (I) and z = 2.3 (II), respectively.