1. Structural and phase composition features of carbon films grown by DC PECVD process A.A. Zolotukhin, A.P. Volkov, A.O. Ustinov, A.N. Obraztsov, Physics Department of Moscow State University

2. Introduction In this work we present the results of in-situ and ex-situ Raman spectroscopic examination of CVD diamond films deposited in a DC discharge plasma. Despite a considerable interest in the CVD technology and the wide use of Raman spectroscopy for the characterisation of diamond CVD films, only a few experiments were described in the literature that were devoted to the Raman in-situ diagnostics of diamond films. The in-situ Raman measurements can be used for determining the temperature of films, because conventional optical pyrometry is hindered by intense emission from the plasma region. Position of Raman lines may also change as a result of the mechanical stresses developed in the material application of an external load.

3. Scheme of Experimental Setup Scheme of a setup for in-situ monitoring of the Raman spectra.

4. COMPOSITION AND SURFACE MORPHOLOGY STUDIES RS of typical polycrystalline diamond SEM Image of typical diamond polycrystalline CVD film

5. RS of nanocrystalline diamond AFM image of typical diamond nanocrystalline CVD film

6. RS of CVD graphite-like film material SEM image of typical graphite-like CVD film

7. HRTEM of a fragment of carbon nanotubes in the CVD film TEM image of typical graphite-like CVD film

8. Raman spectra measured in situ in the course of carbon deposition: (1) amorphous carbon film; (2) diamond film composed of nanocrystals; (3) diamond film composed of a well crystallites. In-situ Raman spectroscopy of CVD diamond films

9. Raman spectra of diamond films measured in-situ at various time instants after the begining of deposition: (1) 15; (2) 30; (3) 45 min;

10. Raman spectra of diamond films measured in-situ at various substrate temperatures: (1)25; (2)1000; (3) 1200°C. Position of the “diamond” Raman line (1332cm -1 ) versus the film temperature: (points) this experiment; (dashed line) the plot measured on a diamond single crystal C. Johnson, A. Crosley, P.R. Chalker, et al., Diamond and Related Mat., 1 (1992) 450. the experiment

11. Raman spectra of a diamond film measured in-situ at various time instants after the begining of its etching in a hydrogen plasma: (1) 15; (2)30; (3)45; (4)60; (5)90 min. Position of the “diamond” Raman line (1332 cm -1 ) versus the pressure:(dashed line) the plot measured on a diamond single crystal; (points) polycrystalline diamond film measured in-situ in the course of etching in a hydrogen plasma. M. Hanfland and K.Syassen., J. Appl. Phys., 1985, vol.57, p. 2752. the experiment

12. Conclusions The CVD method was used for fabrication of different thin film carbon materials. Their structural, morphology, phase composition properties were studied by a number of experimental methods including Raman, SEM, STM, AFM, TEM, HRTEM. The original in-situ Raman spectrometer was elaborated and a set of experiments performed to study specificity of the diamond CVD growth in plasma activated by DC discharge.