A simulation model is presented for nonplanar CVD over device feature scale structures. The direct simulation Monte Carlo method is used to describe the rarefied gas transport in a localized region above the feature. A new approach is outlined to simulate the evolution of the film profile which provides dynamic step-coverage performance and microstructural detail of the growing film. The method allows simulations of nonequilibrium effects resulting from rarefaction of the gas above surface features. Results of a parametric study are presented for deposition within a long narrow trench and a cylindrical contact hole. The parameters investigated include the reactive sticking coefficient, the surface mobility of the adsorbed reactants, the Knudsen number (the ratio of the mean-free path to the feature scale), the feature aspect ratio and feature geometry. A sample calculation is presented for deposition over a square hole structure to demonstrate the extension to realistic three-dimensional structures.