Initial growth of nanocrystalline diamond/β-SiC composite films: A competitive deposition process

Abstract

Although nanocrystalline diamond/β-SiC composite gradient interlayers have been successfully deposited in dealing with the problem of diamond thin-film adhesion to metallic substrates, initial growth process of the two components has not been described, so far. In this letter, we propose that the deposition of composite interlayer is possible because of a selective growth process of diamond and β-SiC phases. There is a competition between the diamond and the β-SiC crystallites to occupy the spaces available on the substrate. The space competition is during the initial nucleation period of the process and also during film growth, leading to the formation of the nanocrystalline composite. The secondary nucleation of β-SiC on the existing diamond surfaces depends on the flux of incoming β-SiC forming gas species. This provides us with a possibility to control phase structure and composition of the composite film by adjusting the tetramethyl silane flow rate.

Thermodynamic Aspects of Diamond/β‐SiC Composite Films

“…This indicates that CH 4 participates actively in the deposition process. This correlates well with the evolution of CH 3 . The mole fractions of CH 4 and CH 3 are mainly controlled by the temperature and the H atom mole fractions that govern the fast equilibration among CH 4 , CH 3 , and CH 2 .…”

“…This correlates well with the evolution of CH 3 . The mole fractions of CH 4 and CH 3 are mainly controlled by the temperature and the H atom mole fractions that govern the fast equilibration among CH 4 , CH 3 , and CH 2 . This equilibration leads to the increase of CH 3 with an increasing temperature.…”

“…The mole fractions of CH 4 and CH 3 are mainly controlled by the temperature and the H atom mole fractions that govern the fast equilibration among CH 4 , CH 3 , and CH 2 . This equilibration leads to the increase of CH 3 with an increasing temperature. CH 3 appears with other hydrocarbon species when TMS is increased to avoid a nearly complete C conversion to C 2 H 2 and hydrogen conversion into H 2 .…”

Diamond/β-SiC Composite Thin Films: Preparation, Properties and Applications

“…It reveals that there exists a space competition between diamond and β-SiC to occupy the spaces available on the substrate during growth [8]. Figure 2.3a shows the crosssectional SEM images of one composite film.…”

“…The schematic illustration of the initial nucleation and growth process is shown in Fig. 2.3b [8]. At the initial growth stage, islandlike diamond and layerlike β-SiC crystals grow.…”