Silicon-germanium (SiGe) hetero-junction bipolar transistor current transients induced by pulse laser and heavy iron are measured using a real-time digital oscilloscope.These transients induced by pulse laser and heavy iron exhibit the same waveform and charge collection time except for the amplitude of peak current.Different laser energies and voltage biases under heavy ion irradiation also have impact on current transient,whereas the waveform remains unchanged.The position-correlated current transients suggest that the nature of the current transient is controlled by the behavior of the C/S junction.