NEUTRON RADIATION TOLERANCE OF ADVANCED UHV CVD SIGE HBT BICMOS TECHNOLOGY/

The effects of 1.0 MeV neutron irradiation on both SiGe heterojunction bipolar transistors (HBTs) and Si CMOS transistors from an advanced u ltra high vacuum chemical vapour deposition (UHV/CVD) SiGe BICMOS tech nology are examined for the first time over the temperature range of 3 00K to 84K. Results at 300K indicate that this Sice technology is robu st with respect to neutron radiation. At fluences as high as 10(15) n/ cm(2) (1.0 MeV equivalent) the devices exhibited a degradation of less than 30% in peak current gain. The SiGe HBTs maintain a current gain of 60 after 10(15) n/cm(2) at 84K, compared to the Si BST which degrad es with cooling to a current gain of 20 at 84K. The cutoff frequencies of both the Si and SiGe transistors are unaffected by neutron irradia tion, and only a slight degradation in the maximum oscillation frequen cy of the transistors was observed.