Local heteroepitaxy of diamond on silicon (100):mA study of the interface structure

Abstract

An extensive study of the interface between highly oriented chemical vapor deposition diamond films and silicon has been performed using atomic force microscopy ͑AFM͒, high-resolution scanning electron microscopy ͑HRSEM͒, x-ray photoelectron diffraction ͑XPD͒, and transmission electron diffraction. The initial roughness of the silicon substrate has been investigated by AFM. Hydrogen plasma has been found to produce pits on the biased substrate surface. The local order of the ␤-SiC grown on silicon ͑100͒ during the biasenhanced nucleation step has been investigated by XPD through the C 1s and the Si 2p intensity modulations. Differences in the XPD diffraction features have been studied and found to be due to the element and energy dependence of the scattering effect. The preferential orientation of the diamond nuclei with respect to the silicon substrate has been quantified by comparison of HRSEM pictures and XPD patterns. Only 30-40 % of the crystallites have been found to be oriented relative to the substrate at an early growth stage of a highly oriented diamond film. The partial heteroepitaxy of the diamond nuclei has been confirmed by transmission electron microscopy through electron diffraction and bright-and dark-field images. Simulations of the XPD patterns induced by tilted and azimuthally rotated diamond crystallites have been performed in order to reproduce the smeared-out features of the experimental diffractograms. The short-range order of the diamond lattice at this early growth stage has been found. The amount of carbon on the silicon substrate has been measured by x-ray photoelectron spectroscopy and HRSEM. Comparing the results, we postulated the existence of carbon domains which are too small to be or become diamond nuclei and are etched away by the hydrogen plasma during the growth process.

Diamond growth by chemical vapour deposition

“…The ionic species react with the substrate, resulting in the formation of a silicon carbide layer with improved adhesion when silicon is used as the substrate [106]. Nucleation densities higher than 1×10 11 cm -2 have been obtained with this method [107], however, Maillard-Schaller et al reported surface damage induced on a silicon substrate during the BEN that happened in the form of holes that could be as deep as 2-3 µm and as large as 200-300 nm in diameter [108].…”

Temperature dependence of silicon carbide interface formation: A photoelectron spectroscopy study

“…We are therefore reluctant to draw any conclusions on the presence of a specific SiC structure in the surface layer, although other investigations have shown that ␤-SiC is frequently formed on Si͑100͒ substrates. 9,11,20 The analysis of the C 1s and Si 2p core level also shows the evolution of a carbide interface and, for temperature below 900°C, the growth of the carbon overlayer as already described in the previous paragraph. In addition, the analysis of the XPS core-level spectra enables us now to separate the contributions from the carbide interface, the substrate, and the overlayer.…”

Diamond CVD by a Combined Plasma Pretreatment and Seeding Procedure

“…This method has also been used to fabricate diamond-based device structures, [20,21] and to deposit highly oriented diamond films using Ir/SrTiO 3 substrates, with promising results, [22] but this method may damage the substrate. Maillard-Schaller et al [23] reported surface damage on a silicon substrate in the form of holes that could be as deep as 2-3 mm and as large as 200-300 nm in diameter. After the nucleation step, the growth is followed by diamond deposition in a standard CVD reactor, under proper growth conditions (GC).…”