RAMAN-SPECTROSCOPY OF ANNEALED CARBON NITRIDE FILMS DEPOSITED BY RF-MAGNETRON SPUTTERING

Amorphous carbon-nitrogen films deposited by RF-magnetron sputtering o nto Si substrates were annealed in vacuum in the temperature range of 300-800 degrees C during 30 min, with no sequential treatment. The fil ms were analyzed by Raman spectroscopy, used as a probe of microstruct ural modifications induced by thermal treatment. The main features obs erved in the Raman spectra are two broad bands at similar to 1360 cm(- 1) (D-band) and similar to 1575 cm(-1) (G-band), characteristic of amo rphous carbon materials. The ratio between their intensities (I-D/I-G) is found to increases with the annealing temperature. Additionally, t he spectra present other two weak bands, one at similar to 700 cm(-1) (I-700) and another at 2230 cm(-1) (I-2230). Normalized against the G- band, their intensities present opposite temperature dependence: I-700 decreases by a factor of three, while I-2230 increases by the same fa ctor in the temperature range studied here. A strong reduction of the luminescence background with the annealing temperature is observed. Th ese results indicate a substantial reduction of the dangling bonds acc ompanied by an increase of the number of C=N bends and of the size, or the number, of the graphitic domains. (C) 1998 Elsevier Science S.A.