Species characterization for a direct-current-biased hot filament growth of diamond using spatial resolved optical emission spectroscopy

Spatial resolved optical emission spectroscopy was applied for a direct-current biased hot filament diamond growth system with a spatial resolution of better than 1 mm. Emission lines from atomic hydrogen, CH, CH+, H-2, and Ar were observed in the visible region. It is found that emission intensity of all the observed lines decreases rapidly as the probe distance from the filament center raises. and increases near the substrate surface. The relative concentration of atomic hydrogen has been estimated by using the emission line of Ar at 750.4 nm as an actinometer. The concentration of atomic hydrogen decreases from filament to the substrate and drops sharply at the substrate surface. The emission spectra and the distribution of hydrogen atom along the substrate surface have also been measured, which are closely correlated with the homogeneity of diamond film growth. And the low concentration of atomic hydrogen at the edge of the substrate results in a worsening of diamond films. (C) 1996 American Institute of Physics.