Reported are the results of a Raman spectroscopic study of a set of chemical-vapor-deposited (CVD) diamond wafers of known thermal conductivity (k). The spectra are obtained at laser wavelengths 514.5, 785 and 1064 nm. The Raman features of these spectra, diagnostic of diamond quality and perfection, are correlated with the room temperature thermal conductivity. Examined are the frequency position, relative intensity, and bandwidths of the diamond Raman line at 1332 cm-1 and the relative abundance of non-diamond carbon components giving rise to the Raman bands at -1355 and -1550 cm-1 characteristic of disordered graphitic and amorphous carbon. The observed increased sensitivity to the scattering from sp2-bonded carbon, through the FT-Raman spectra excited at 1064 nm, allows the sensitive detection of non-diamond carbon impurities. From this can be derived a correlation of the Raman data with thermal conductivity that makes use of the integrated band intensity ratio, I(1332)/I(1550) expressing the relative abundance of sp3-to sp2-bonded carbon. The spectra are analyzed by curve-fitting in terms of four spectral components over the Raman range 1000-1800 cm-1.
Citation: Journal of Materials Research
Volume: 16 No. 6
Pub Type: Journals
CVD diamond, diamond films, materials analysis, microanalysis, raman spectra, raman spectroscopy