Following irradiation, the gain of Si bipolar transistors could be improved by annealing at 350K. It was shown that both the number of defects measured by deep level transient spectroscopy and the gain could be restored to the post irradiation state by injection of minority carriers. One could cycle between the post irradiation state and the 350K annealed state by alternating minority carrier injection at 300K with zero- or reverse-bias anneals at 350K. The structure of the bistable defects was not known, but it was observed that they affect capture kinetics into the shallow charge state of the Si divacancy defect, V2 (=/−). This suggested that the bistable defects were located within the neutron or ion damage cluster.

Gain and Defect Bi-Stability in Radiation Damaged Silicon Bipolar Transistors. R.M.Fleming, C.H.Seager, D.V.Lang, E.Bielejec, J.M.Campbell: Physica B, 2007, 401-402, 21-4