Development of In-situ Raman Analysis of Plasma Deposited Diamond

摘要

Progress towards the development of in-situ Raman capabilities for plasmadeposited diamond films is described. The shift and broadening of the first order Raman-active phonon mode in natural and synthetic diamond is analyzed at temperatures within the range commonly employed in vapor phase diamond deposition (>1000K). At these temperatures, we have found that the Anti-Stokes component to the Raman signature can be detected and employed as an alternative diagnostic. We describe preliminary results in which in-situ Raman is employed to monitor the temperature of a heated natural diamond substrate exposed to both molecular and atomic hydrogen. We find that variations in molecular hydrogen fraction in the reactant gas mixture can lead to substantial variation in substrate temperature. Following exposure to atomic hydrogen, the Raman line center is found to be shifted to lower energy (at ambient temperatures). The shift is in part attributed to the presence of interstitial hydrogen. (jhd)