AFM study on the non-monotonic texture evolution of heteroepitaxially nucleated diamond films

Abstract

After the heteroepitaxial nucleation of diamond on Si(001) the texture of the film depends strongly on the subsequent growth process. According to the van der Drift mechanism of evolutionary selection, a growth parameter α slightly below 3 should result in a splitting of the central pole density maximum at χ = 0 ° in the {400} pole figure into four maxima for high film thicknesses. In contrast, a strong narrowing of this maximum for the studied films was observed experimentally. Based on simple geometric considerations a two-dimensional simulation is presented which shows that in the growth competition between two selected grains for α < 3 the preferred crystallite which will finally survive may occupy considerably less volume and surface area in an intermediate stage of film growth. Atomic force microscopy (AFM) has been used in order to test whether this non-monotonic behaviour has an influence on the macroscopic film texture resulting in a transient narrowing of the pole figure. The measured correlation between the tilt angles and the mean areas of the top {001} facets supports the assumption that the effect described by the simulation contributes to the observed texture evolution.