Analysis of the fine structure of the Raman line and of X-ray reflection profiles for textured CVD diamond films

Abstract

Textured diamond films prepared by CVD were studied by X-ray measurements and Raman spectroscopy in the high dispersive mode in order to get structural information. A 〈100〉 fibre texture is observed for the films prepared with a 2% methane concentration and a low substrate temperature. For all the 2% CH4 samples the diffraction spectra reveal an important broadening of the 111 reflection and two additional bands at about 0.207 and 0.217 nm attributed to stacking faults along the 〈111〉 direction. Domains of hexagonal symmetry can then locally be formed with the defect ordering. The recording of a 1322 cm−1 Raman line generally attributed to the lonsdaleite or hexagonal diamond polytypes supports this assumption. This 〈100〉 fibre texture is recorded for samples obtained with a high methane concentration (2%) related to a fast growth rate, which may explain these stacking faults along the 〈111〉 direction.