Analysis of optical emission spectroscopy in diamond chemical vapor deposition

We used optical emission spectroscopy (OES) to study the gas phase chemistr y in hot filament chemical vapor deposition (HFCVD) diamond processes. The results show that the methane concentration strongly influenced the intensi ty ratios of CH, CH+ and H-gamma to H-beta, and the effects of the pressure and filament temperature on the relative concentrations of the species wer e also analyzed. Spatially resolved OES implied that a relative high concen tration of atomic H existed near the substrate surface, which is favorable for diamond film growth. Although the relatively high concentrations of CH and CH+ to atomic H are beneficial to increasing diamond nucleation density , they are very harmful to the growth of diamond films. (C) 2000 Elsevier S cience S.A. All rights reserved.