Studies of N self-diffusion in the amorphous precursor-derived ceramics were carried out by using ion-implanted stable 15N as a tracer, and secondary ion mass spectrometry for depth profiling. Analysis of the diffusion profiles at 1500 to 1700C did not yield the Gaussian broadening typical of implantation profiles. A high-concentration region was instead observed, in which the width of the implantation profile was almost unchanged by implantation damage, plus a low-concentration region in which diffusion occurred. The experimentally determined diffusivities (figure 29) obeyed the Arrhenius law, with an activation enthalpy of about 7eV and a pre-exponential factor of the order of 5m2/s. This indicated diffusion via vacancy-like defects.

Self-Diffusion Studies of 15N in Amorphous Si3BC4.3N2 Ceramics with Ion Implantation and Secondary Ion Mass Spectrometry. H.Schmidt, G.Borchardt, S.Weber, S.Scherrer, H.Baumann, A.Müller, J.Bill: Journal of Applied Physics, 2000, 88[4], 1827-30