Defects in N-doped diamond films, produced by hot filament chemical vapor deposition were studied by using electron spin resonance, Raman spectroscopy and scanning electron microscopy. The peak-to-peak electron spin resonance line-width varied from 0.36 to 0.52mT and depended upon the N concentration in the processing gas. In the case of N-doped diamond films, electron spin resonance spectrum exhibited a hyperfine structure that was typical of an NS0 paramagnetic center. The shape of the central electron spin resonance line showed that it was a superposition of 2 components: a narrower Lorentzian and a broader Gaussian one, characterized by different saturation behavior. With increasing N concentration in the processing gas, the ratio of the Gaussian and Lorentzian integral intensities of the electron spin resonance spectrum also increased. The Raman spectra showed that, with increasing doping level, the diamond Raman line at 1332.5/cm broadened, the broad band at about 1530/cm became more pronounced than indicated by the degradation of diamond crystallinity and was in agreement with scanning electron microscopic observations.Paramagnetic Defects in Diamond Films Synthesized by the Hot Filament Chemical Vapour Deposition. A.Banaszak, K.Fabisiak, M.Kaczmarski, M.Kozanecki: Crystal Research and Technology, 2006, 41[6], 535-40