The introduction of B into As sites, as deduced from the strength of vibrational modes at 601.7 and 628.3/cm, was studied as a function of the fluence of 2MeV electrons. Simultaneous monitoring of the strength of the Is-2p electronic transitions of neutral shallow acceptors, and of the neutral 0.078eV acceptor and its singly-ionized 0.203eV level, provided accurate data on the position of the Fermi level during irradiation. The results were inconsistent with previous models for the location of B on As sites. A model was proposed which was based upon the onset of enhanced B diffusion when the Fermi level lay above 0.078eV.

W.J.Moore, R.L.Hawkins: Journal of Applied Physics, 1988, 63[12], 5699-702