Using deep level transient spectroscopy and Laplace-deep level transient spectroscopy, an investigation was made of the vacancy-related defects which were created in B-doped epitaxial Si by 2MeV electron irradiations at temperatures below 40K. The vacancy level was found at Ev + 0.12eV together with a deep level transient spectroscopic peak at Ev + 0.20eV which annealed out at about 140K and was tentatively identified as being a vacancy in a different configuration. The emission rate of the dominant vacancy-related deep level in the temperature range from 200 to 550K, namely the (0/+) transition of the di-vacancy (V2), displays a very large dependence of the emission rate on the electric field strength in the depletion region of the diodes. This dependence was unexpected in terms of the classical Poole¯Frenkel effect, given the neutral charge state of V2 before hole capture. The effect of high fields appeared to be caused by phonon assisted tunneling. When V annealed out at around 200K, a new complex assigned to a vacancy¯B pair gave rise to 2 charge states. Quenching experiments with reverse bias showed that the complex was bistable. It annealed out at 260K.

On-Line DLTS Investigations of the Mono- and Di-Vacancy in p-Type Silicon after Low Temperature Electron Irradiation. N.Zangenberg, J.J.Goubet, A.Nylandsted Larsen: Nuclear Instruments and Methods in Physics Research B, 2002, 186[1-4], 71-7