Nucleation and initial growth phase of diamond thin films on (100) silicon

Abstract

The nucleation of diamond on silicon (100) in a methane-in-hydrogen microwave plasma has been investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM), and reflection high energy electron diffraction (RHEED). The nucleation of diamond was performed by application of an electrical substrate potential. It was found that three-dimensional non-facetted islands are initially formed whose sizes increase with the deposition time. In spite of their very small sizes of a few nanometers, RHEED reveals that the islands are of crystalline diamond structure. An induction time of about 6.5 min was necessary for the diamond nucleation, which is partly caused by the formation of a silicon carbide surface layer due to the carbon diffusion into the substrates. The time dependence of nucleation density was investigated and fitted with a model kinetics which considers the formation, destruction, and capture of active sites, germs, and nuclei. Analyses of the first nearest neighbor distance distributions reveal the formation of a depletion zone of nuclei around the existing islands. These results confirm the role of the adatom diffusion improved by the bias-enhanced ion bombardment. Analyses of the island size and the island height distributions show constant growth rate at beginning of the diamond deposition. From the nearly constant ratios of the island height to island size, independent of the nucleation time, one can deduce that the thermodynamics accounts not only for the growth mode, but also for the island shape during deposition. The bias-enhanced ion bombardment during deposition may increase also the diffusion of the surface atoms of the islands, allowing the system to approach equilibrium

Diamond nucleation enhancement by direct low-energy ion-beam deposition

“…[12][13][14] Beckmann et al 15 noted that this change in the plasma chemistry was too small to account for the nucleation enhancement. Jiang, Schiftman, and Klages 16 found that the overall temporal evolution of nucleation density agreed well with a surface kinetic model proposed by Tomellini, Polini, and Sessa. 17 They further suggested that ion bombardment plays a decisive role in the BEN process.…”

“…9. At an ion dose of 10 16 cm Ϫ2 , only two peaks at about 820 and 980 cm Ϫ1 for SiC and Si can be observed. As the ion dose increased to 10 17 cm…”

Effects of the bias enhanced nucleation hot-filament chemical-vapor deposition parameters on diamond nucleation on iridium

“…[11][12][13] On the other hand, for silicon, an enhanced surface mobility of active species during BEN leads to a depletion zone around each diamond nucleus. 14 In the later case, the measured distributions were shifted to larger distances compared to the random case. In the present study, the Poisson analysis of the nearest-neighbor distribution clearly showed that surface diffusion of carbon species on the Ir ͑100͒ surface is not the driving force for nucleation during the HFCVD-BEN step.…”

“…This behavior is quite different from the one reported for BEN-MWCVD process on iridium [11][12][13] and silicon. 14 On iridium, diamond-oriented particles are agglomerated forming domains. [11][12][13] On the other hand, for silicon, an enhanced surface mobility of active species during BEN leads to a depletion zone around each diamond nucleus.…”

Effect of Nucleation Rate on Heteroepitaxial Diamond Growth on Si (100) via Electron-Emission-Enhanced Nucleation by Hot Filament Chemical Vapor Deposition

“…This will be kept layer-by-layer growth due to adatom diffusion. Jiang et al [14] indicated that the first-nearest-neighbor distance among the nuclei was about 10 nm determined by experiments. Thus, Ascarelli et al [15] concluded that the maximum nucleation density was limited at 10 12 cm ± ±2…”