Ionizing radiation tolerance of high-performance SiGe HBT's grown by UHV/CVD

The ionizing radiation tolerance of high-performance SiGe HBTs, grown by UHV/CVD and optimized for 77 K, has been investigated for the first time. Results at both 300 K and 77 K indicate that this SiGe technology is inherently radiation tolerant without additional processing steps. Perimeter-to-area analysis show parallel shifts in the collector and base current density for total radiation doses below 1.0 Mrad(Si). Relatively minor degradation in the current gain characteristics is observed for SiGe HBTs exposed to 1.0 Mrad(Si) of Co/sup 60/ gamma radiation, indicating that the technology is robust for many applications requiring a high degree of ionizing radiation tolerance. 1/f noise measurements made pre- and post-radiation show the appearance of a generation-recombination center in some of the SiGe HBTs after a total-dose exposure to 10.0 Mrad(Si).