Columnar Microstructure in Three-Dimensional Ballistic Deposition

Simulations of ballistic deposition onto a planar two-dimensional substrate at near grazing incidence generate a deposit structure consisting of noncontacting clusters growing at an angle of about 37.5° from the substrate normal. The cluster growth dynamics can be described in terms of the coalescence of moving domain boundaries whose motion is a two-dimensional Eden growth process. This description allows us to obtain exact values for the scaling exponents which chaacterize the internal substructure of the deposit and the roughness of its surface. The roughness increases with the deposit thickness h as h 1/3 .