Defect analyses of nucleation and growth surfaces of cvd diamond

Structural and chemical defect analyses of are-jet cvd diamond growth surfaces (g-CVDD) and nucleation surfaces (n-CVDD) were performed using Auger electron spectroscopy/secondary electron emission spectroscopy (AES/SEE), variable-energy positron annihilation spectroscopy (PAS), and secondary ion mass spectrometry (SIMS). The g-CVDD surface possessed a lower concentration of point defect structures (vacancies, impurities, and their complexes), lower concentration of secondary phases of non-diamond character (amorphous and graphitic C, porosity), a lower concentration and 'shallower' depth distribution of hydrogen and nitrogen, a higher average linear grain intercept and lower equivalent ASTM grain size number, relative to the n-CVDD surface. These orientation-specific defect profiles are attributable to the transition from the initial random nucleation on energetically favorable structural and/or chemical sites of a 'foreign' substrate to a (growth parameter) controlled quasi-epitaxial growth of cvd diamond and provide for through-thickness property gradients. (C) 1998 Elsevier Science B.V.