INDICATIONS OF NONMONOTONIC TEXTURE EVOLUTION FROM A 2-DIMENSIONAL SIMULATION STUDY

The Van der Drift mechanism of evolutionary selection describing the t exture development of polycrystalline diamond films has been studied t heoretically using a very simple two-dimensional model. For alpha para meters below 3, the competition between a perfectly epitaxially aligne d crystallite and a grain which is tilted so that the direction of fas test growth is parallel to the surface normal has been simulated. We h ave quantified the volume fractions of the differently oriented crysta llites with increasing film thickness and thus could distinguish diffe rent regimes for the growth competition. Although the tilted crystalli te will in any case overgrow the perfectly aligned one completely, in the limit of very high film thickness as postulated by the van der Dri ft theory the volume fraction of the latter can be significantly highe r in an intermediate stage of the growth competition. This implies, fo r an intermediate thickness range, rocking curves narrower than expect ed from the value of the or parameter. First experimental results conf irm this prediction.