SiGe BiCMOS technologies are one of the proposed options for the front-end readout electronics of the detectors in the middle region of the ATLAS-Upgrade. The radiation hardness of the SiGe bipolar transistors is being assessed for this application through irradiations with different particles. Biasing conditions during irradiation experiments of bipolar transistors or circuits have an influence on the damage and there is a risk of erroneous results. We have performed several irradiation experiments of SiGe devices in different bias conditions. We have observed a systematic trend in gamma irradiations, showing a smaller damage in transistors irradiated biased compared to those irradiated with shorted or floating terminals. These effects have not been observed in neutron irradiations. (C) 2010 Elsevier Ltd. All rights reserved.