ANALYSIS OF CONTAMINATION IN DIAMOND FILMS BY SECONDARY ION MASS-SPECTROSCOPY

Polycrystalline diamond films grown by hot filament chemical vapor deposition (HFCVD) have been obtained in a tungsten filament reactor, from gaseous mixtures of methane and hydrogen. The films have been analyzed for tungsten impurities by secondary ion mass spectroscopy (SIMS). Boron doping of the films has also been achieved by the addition of a boron nitride source within the reactor chamber. SIMS analysis shows the presence of tungsten or boron within diamond films. The concentration of both impurities are higher in films deposited at lower pressures and with lower methane concentrations. SIMS depth profiles show a maximum concentration of tungsten at the interface between film and substrate; this effect is not apparent in the boron depth profile. © 1992.