A study was made of the degradation of strained Si1-xGex diodes and heterojunction bipolar transistors under electron and neutron irradiation. It was found that, in the case of diodes with x = 0.08, an electron capture level was detected in the SiGe epitaxial layer. This was mainly responsible for an increase in the reverse current under irradiation. In heterojunction bipolar transistors with an x-value of 0.08, a hole and an electron trap were observed in the base region. The electron capture level was associated with an interstitial B complex. Two electron capture levels, which were related to the E center and to the di-vacancy respectively, were also detected in the collector region. Increases in the base current and a decrease in the collector current were attributed to electron capture levels which were introduced into the base and collector regions.

H.Ohyama, J.Vanhellemont, Y.Takami, K.Hayama, T.Kudo, T.Hakata, K.Kobayashi, H.Sunaga, J.Poortmans, M.Caymax: Materials Science Forum, 1995, 196-201, 371-6