Regensburg 2000 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 10: Diamant

HL 10.9: Vortrag

Montag, 27. März 2000, 18:30–18:45, H13

Non-diamond carbon phases on the surfaces of transition metal enhanced polished CVD diamond films — •James A. Weima, Alexander M. Zaitsev, Wolfgang R. Fahrner, Reinhart Job, Gabriele C. Kosaca, and Frank Blum — FernUniversitaet Hagen, FB Elektrotechnik, LGBE, Haldener Str. 182, 58084 Hagen

CVD diamond films thermochemically polished at elevated temperatures on nickel and steal polishing plates were characterized using the micro-Raman spectroscopy. As excitation sources of the Raman set up, a CW He-Ne laser and an argon ion laser both operated at a power of 10 mW on an area of 1 sq. micron were used. Films polished at high temperatures (above 1173 K) showed Raman spectra lines in the range 100-1600 cm-1. The low energy spectra lines between 200-1100 cm-1 found only on optical grade films, appear for the first time in the spectra of polished CVD diamond films. Their existence is attributed to laser stimulated cluster formation of carbon fragments formed on the surfaces of the polished films. A peculiarity of these new features is an increase of the intensity with increasing laser exposure time. The spectra lines found at 1350 cm-1 and 1580 cm-1 can be attributed to nanocrystalline and the microcrystalline graphite phases, respectively. The intensities of these graphite phases show no dependency on the laser exposure time. The temperature dependency of the intensities of the diamond and of the graphite Raman lines was investigated at different polishing temperatures.