The basic mechanisms of defect formation due to ion bombardment during the bias-assisted growth of diamond films were studied. The films were deposited at bias voltages of between -60 and –120V for 2h onto type-Ib monocrystals. A steep increase in dechannelling was found in ion-channelling experiments. In films which were grown at the lowest bias voltage of –60V, the dechannelling increased by a factor of 2 as compared with a 0V reference film. In subsequent samples, deposited at –80V, channelling was already completely suppressed. An analysis of back-scattered Kikuchi patterns indicated that, at up to –85V, the decrease in pattern contrast was caused by defects in the crystal lattice which were equally distributed over the film; rather than by variations in the crystal lattice orientation (mosaicity). According to the Raman spectra, 3 different regimes could be distinguished. At bias voltages of up to –60V, the signal from non-diamond C phases was negligible. At bias voltages of –100V and above, the typical signatures of amorphous and graphitic C phases were found in the spectra. In the third regime, at about –80V, these spectral features exhibited a pronounced fine structure and a marked enhancement in intensity.

Bias Assisted Growth on Diamond Single Crystals - the Defect Formation due to Ion Bombardment Studied by Ion Channelling, Electron Backscatter Diffraction and Micro-Raman Spectroscopy. M.Schreck, C.Grunick, C.Haug, R.Brenn, B.Stritzker: Diamond and Related Materials, 2002, 11[3-6], 487-92