Articles you may be interested inCompositional mapping of the argon-methane-hydrogen system for polycrystalline to nanocrystalline diamond film growth in a hot-filament chemical vapor deposition system Silver on diamond Schottky diodes formed on boron doped hotfilament chemical vapor deposited polycrystalline diamond filmsThe morphology changes in diamond synthesized by hotfilament chemical vapor depositionThe growth kinetics of diamond film has been studied, grown by a hot-filament chemical vapor deposition method, to obtain a fundamental information for the growth process of diamond from the gas phase. In order to study the growth kinetics of a pure diamond, the deposition conditions for high-quality diamond are first determined and the kinetics study is carried out under these deposition conditions. Diamond film thickness is directly proportional to the deposition time. This indicates that diamond films are deposited in the steady state under these experimental conditions. The variation of growth rate with substrate temperature shows a distinct maximum. The maximum temperature is shifted somewhat to the higher temperature side with increasing methane concentrations. It is found that this behavior is due to the decrease of supersaturation with increasing substrate temperature. However, the growth rate of diamond film increases linearly with methane concentrations. Therefore, the growth rate of diamond film can be described by the rate constant for a first-orderreaction. From the kinetic data of diamond deposition, the deposition rate is controlled by the surface reaction (activation energy of 11 kcal/mol) at the lower temperature range, while the deposition rate is gas phase diffusion controlled (activation energy of 3.8 kcal/mol) at the higher temperature range.

The interfaces between diamond films and silicon substrate have been investigated to obtain a better understanding of the characteristics of diamond-substrate interface. In order to investigate the interface morphology, the backside surface of diamond film and the substrate surface have been observed after the deposited diamond film is separated from the silicon substrate. The vacant space between particles is found on the backside surface of the separated film and the central part of each particle caves in. Also, many of the hillocks are present on the Si substrate surface after the film is removed. From the observations, it is found that the interfaces between the diamond film and the silicon substrate is very rough. It is suggested that such interface morphology is attributed to the etching of the silicon substrate which takes place at the early stage of the synthesis. For the energy dispersive spectroscopy experiment of the backside surface of the separated film, more silicon is detected at the central part of each particle. This result implies that strong Si—C bonds are localized at the center of each particle, which would result in the poor adhesion.

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