Growth of diamond on α-(0001) sapphire substrates

Diamond growth on faceted sapphire and the charged cluster model

“…The reevaporation of subcritical nuclei thus prevents the formation of stable nuclei and the eventual formation of diamond particles. The observation that no suppression of diamond formation occurs when the sapphire substrate has been abraded with diamond powder [7] seems to support this suggestion. Since a fairly large amount of diamond residue can be embedded as a result of the abrading process, a high nucleation density is possible.…”

“…In particular, the presence of aluminium carbide at 281.4 eV binding energy is not detected [15]. It should be noted that the existence of a graphitic, diamond-like carbon or amorphous carbon intermediate layer is not likely, as in our previous work, we had analysed the underside of the delaminated diamond film as well as the sapphire substrate surface and found that diamond grew directly on the sapphire substrate [7]. sapphire surface even after 4 h of diamond deposition.…”

“…Diamond was deposited for various periods between 15 min and 4 h with 1 vol% methane in hydrogen gas mixture at the filament and substrate temperatures of 2100 and 850 1C, respectively. Details of the HFCVD reactor were also described elsewhere [7]. The deposition parameters were similar to those used by Hwang et al [2] for the CCM and thus would serve as a good basis to investigate the formation of diamond within the CCM.…”

Tof-Sims Fragment Pattern Analysis Of Boron-Doped Chemical Vapour Deposition Diamond

“…Figure 4 also shows the presence of CH -, C2H -, C2H3at m/z = 13, 25 and 27, respectively. While it is possible that CxHyfragments may have originated from the CVD diamond due to a copious amount of hydrogen in the CVD environment during the fabrication process (Saw et al, 2003;Saw & du Plessis, 2005), we attribute them to adventitious hydrocarbons on the sample surface. The SO3peak at m/z = 79.9570 as well as the Cl -, CN -, CNOand several CxHyOz fragments are attributed to atmospheric aerosol particles on the sample surface (Zhang et al, 2016;Zhu, Olson, & Beebe, 2001).…”

Effect of diffusion length on the nucleation of chemical vapour deposition diamond

“…While the hydrocarbon species that are not adsorbed may leave the substrate surface by desorption into the gas phase again, the adsorbed species decompose into carbon atoms before diffusing along the substrate surface or into substrate, forming an intermediate layer. In the case of diamond deposition on sapphire substrate, there is no formation of an intermediate layer [3,8,9]. Due to the absence of an intermediate layer, no incubation period is observed and diamond nucleation occurs directly on the sapphire surface as a result of the surface diffusion of the adsorbed carbon atoms.…”