Bias-enhanced Nucleation of Diamond in Hot Filament CVD

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J. Korean Ceram. Soc. > Volume 34(6); 1997 > Article

Journal of the Korean Ceramic Society 1997;34(6): 636.

열필라멘트 CVD에서 전압 인가에 의한 다이아몬드의 핵생성 촉진

최균, 강석중, 황농문¹

한국과학기술원 재료공학과
¹한국표준과학연구원 미세조직그룹

Bias-enhanced Nucleation of Diamond in Hot Filament CVD

ABSTRACT

The effect of various processing parameters, in particular the substrate and filament temperature, on the nucleation of diamond has been studied for the hot filament CVD process with a negative bias on the substrate. As far as the substrate temperature was maintained around the critical temperature of 73$0^{circ}C$, the nucleation of diamond increased with increasing filament temperature. The maximum nucleation density of ~ 2$times$109/$textrm{cm}^2$ was obtained under the condition of filament temperature of 230$0^{circ}C$, substrate temperature of 75$0^{circ}C$, bias voltage of 300V, methane concentration of 20%, and deposition time of 2 hours. This nucleation density is about the same as those obtained in previous investigations. For fixed substrate temperatures, the nucleation density varies up to about 103 times depending on experimental conditions. This result is different from that of Reinke, et al. When the substrate temperature was above 80$0^{circ}C$, a silkworm~shaped carbon phase was co-deposited with hemispherical microcrystalline diamond, and its amount increased with increasing substrate temperature. The Raman spectrum of the silkworm-shaped carbon was the same as that of graphitic soot. The silkworm-shaped carbon was etched and disappeared under the same as that of graphitic soot. The silkworm-shaped carbon was etched and disappeared under the deposition condition of diamond, implying that it did not affect the nucleation of diamond.

Key words: Diamond, BEN, Hot filament CVD, Nucleation density