No abstract

The influence of the injection of minority charge carriers on the formation of a divalent bistable defect (DBH) having two energy levels of Ev + 0.44 eV and Ev + 0.53 eV in its metastable configuration is investigated. Using forward current injection, the formation temperature of this defect in p‐type silicon can be lowered by about 50 °C. The production of such bistable defect is enhanced in materials with a high ratio of boron to carbon concentrations. This allows one to conclude that the boron atom is one of the constituents of the defect under study. There is also a correlation between the behavior of the bistable hole traps and a metastable electron trap observed earlier. It is concluded that these traps are related to metastable and stable configurations of the DBH defect, which has inverse occupancy level ordering in its stable configuration.

Using forward current injection with densities in the range 15-30 A/cm 2 we can effectively eliminate the radiation-induced boron-oxygen complex, which is the main compensating center in irradiated Si solar cells. It was found that for a given forward current density the elimination rate is decreasing with increasing irradiation dose. Additionally, some evidences have been obtained on the negative-U properties of the radiationinduced boron-oxygen complex.

Comparative studies employing Deep Level Transient Spectroscopy and C-V measurements have been performed on recombination-enhanced reactions between defects of interstitial type in boron doped silicon diodes irradiated with alpha-particles. It has been shown that self-interstitial related defects which are immobile even at room temperatures can be activated by very low forward currents at liquid nitrogen temperatures. Their activation is accompanied by the appearance of interstitial carbon atoms. It has been found that at rather high forward current densities which enhance BiOi complex disappearance, a retardation of Ci annealing takes place. Contrary to conventional thermal annealing of the interstitial boron-interstitial oxygen complex, the use of forward current injection helps to recover an essential part of charge carriers removed due to irradiation.

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.We present experimental and theoretical results showing that the migration of interstitial carbon atom (C i ) in silicon depends on its charge state. The experimental results were obtained from the analysis of changes in concentrations of the C i defect, which were determined from deep level transient spectra, in n þ -p diodes subjected to irradiation with 4-6 MeV electrons or a-particles at T 273 K and subsequent heat-treatments in the temperature range 280-330 K with applied reverse bias voltage and without it. It has been found that in the positive charge state the C i migration energy is 0.88 AE 0.02 eV, while in the neutral charge state it is reduced to 0.73-0.74 eV.First-principles density-functional calculations of the structure of C i in different charge states (z ¼ 0, þ1, À1) and diffusion coefficient parameters (activation barrier DE a and preexponential factor D 0 ) have been performed. It has been found that a split-h100i configuration with C 2v symmetry is the most stable one for C i in all the charge states.