On the {111} <111> penetration twin density in CVD diamond films

Abstract

Abstract The morphology of isolated crystals and polycrystalline films can thoroughly be influenced by twin nucleation. In order to obtain more insight into this rather complicated subject a new theoretical concept, called the nucleation surface, is introduced and worked out quantitatively. The nucleation surface on a given position of a crystal facet is proportional to the probability that the given position is overgrown by a twin, which has nucleated at an earlier time. It is calculated in detail for {111} <111> penetration twins on diamond facets, as a function of the position on the {111} plane and of the geometrical parameter α = √3 ν100/ν111. The analytical and numerical results show that the twin abundance depends strongly on both parameters. The calculations account well for a number of experimental observations.