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

The self-diffusion of boron is studied between 1550 and 1700 degrees C in polymer-derived amorphous solids of composition Si3BC4.3N2. Ion implanted stable B-10 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 Delta H = (7.3 +/- 1.3) eV and a high pre-exponential factor of D-0 = 1.6 m(2)/s. The results are discussed in relation to the diffusivities of the other constituents (Si, C, N) and possible diffusion mechanism are suggested. (c) 2007 Elsevier B.V. All rights reserved.