Poly-adamantane as precursor for low temperature chemical vapor deposition of nanocrystalline diamond films

Abstract

Nanocrystalline diamond (NCD) films are technologically important tribological coatings and their large area, uniform growth is needed for a wide range of applications. The conventional growth of NCD requires the seeding of the foreign substrates by detonation nanodiamond particles. In terms of diamond seeds for subsequent NCD film deposition, the use of chemical precursor offers advantages in producing higher purity and higher crystallinity nanodiamond particles than that by detonation method. However, the easy sublimation of chemical precursor in plasma is a serious drawback. Here we report that the poly-adamantane layer formed by the photochemically induced polymerization of adamantane serves as a promising precursor for the growth of wafer scale NCD film using linear antenna plasma-assisted chemical vapor deposition at 500 °C. TEM cross-section analysis of the interface reveals the formation of well-faceted diamond nuclei within the amorphous carbon matrix (sp 3 % ~ 40 %) decomposed from poly-adamantane. The influence of plasma chemistry on the nucleation process was also discussed. Our work provides guidance for low-temperature deposition of high-quality NCD film by chemical nucleation. • Deposition of 4-in. nanocrystalline diamond wafer using 230 nm-thick poly-adamantane precursor layer • Cross-sectional TEM study of diamond nuclei derived from poly-adamantane precursor • Study of plasma chemistry on nucleation process by poly-adamantane precursor • Film quality control by poly-adamantane precursor at low temperature