Atomic diffusion of boron and other constituents in amorphous Si–B–C–N

The self-diffusion of boron is studied between 1550 and 1700 °C in polymer-derived amorphous solids of composition Si3BC4.3N2. Ion implanted stable 10B isotopes are used as tracers and secondary ion mass spectrometry for depth profiling. The experimentally determined diffusivities obey an Arrhenius behavior with a high activation enthalpy of ΔH = (7.3 ± 1.3) eV and a high pre-exponential factor of D0 = 1.6 m2/s. The results are discussed in relation to the diffusivities of the other constituents (Si, C, N) and possible diffusion mechanism are suggested.