Simulation of polycrystalline 3D film growth. An investigation of the evolution of grain size and texture in diamond films

An analytical method for simulating gas phase film growth has been developed and used to study the growth of diamond films during prolonged deposition, i.e. the film thickness is much larger than the lateral grain size. From a model system composed of 10(exp 4) grains, reliable results can be evaluated for the growth of diamond films by (111) and (001) deposition under different initial conditions and with varying growth parameters. It is demonstrated that the rate of structure evolution is sensitively influenced by the aspect ratio of diamond crystal. A near-linear proportionally between the average grain size and the thickness of films can be approximately yielded for a large film thickness which is about 10 times of the average distance of the nuclei. The proportionality constant varies for a statistical nucleation from 0.0056 to 0.43 by changing the aspect ratio. Furthermore, the orientational distribution is drastically narrowed down so that the probability of coalescence of grains with a slight orientational difference is considerably increased.