Search

The total dose effects of 50 MeV lithium (Li3+) ions on 200 GHz (8HP) silicon-germanium heterojunction bipolar transistors (SiGe HBTs) are studied in total doses ranging from 300 krad to 10 Mrad. The different electrical characteristics, such as the Gummel characteristics, dc current gain (hFE), neutral base recombination, avalanche multiplication of carriers (M-1) and output characteristics (IC-VCE), were studied before and after Li3+ ion irradiation. The results of 50 MeV Li3+ ion irradiation on SiGe HBTs are compared with 60Co gamma irradiation results in the same dose ranges. [ABSTRACT FROM AUTHOR]

• The reliability of Si BJTs and SiGe HBTs were studied under different LET radiations. • The SRIM/TRIM simulations were employed to analyze the energy loss phenomenon. • Both radiations were cause substantial degradation in device parameters. • The SiGe HBTs are more radiation hardened than Si BJTs. The reliability of silicon bipolar junction transistors (Si BJTs) and silicon germanium heterojunction bipolar transistors (SiGe HBTs) were studied under 80 MeV nitrogen (N6+) ions and 60Co gamma radiation in a total dose from 1 to 100Mrad at 300 K. Different DC electrical parameters namely Gummel Characteristics (I B , I C –V BE), excess base current (ΔI B), current gain (h FE), and output characteristics (I C –V CE) were studied before as well as after being subjected to radiations. Both radiations caused substantial degradation in parameters such as an increase in I B , a decrease in the h FE , and a decrease in I Csat. The parametric degradation is more in Si BJT (99% degradation in h FE after ion irradiation) when compared to SiGe HBT (45% degradation in h FE). The SRIM/TRIM simulations were employed to analyze the energy loss phenomenon and ion range in device structures. Annealing studies were also conducted to study the recovery behavior of irradiated devices. The influence of linear energy transfer (LET) of radiations on damage mechanism is also discussed based on irradiation and annealing results. The results show that SiGe HBTs are more radiation hardened than Si BJTs. [ABSTRACT FROM AUTHOR]

Abstract: We have investigated the effects of 50MeV lithium ion irradiation on the DC electrical characteristics of first-generation silicon–germanium heterojunction bipolar transistors (50GHz SiGe HBTs) in the dose range of 600krad to 100Mrad. The results of 50MeV Li3+ ion irradiation on the SiGe HBTs are compared with 63MeV proton and Co-60 gamma irradiation results in the same dose range in order to understand the damage induced by different LET species. The radiation response of emitter–base (EB) spacer oxide and shallow trench isolation (STI) oxide to different irradiation types are discussed in this paper. We have also focused on the efficacy in the application of a Pelletron accelerator to study total dose irradiation studies in SiGe HBTs. [Copyright &y& Elsevier]

Abstract: The thermodynamic stability of device-relevant epitaxial SiGe strained layers under proton irradiation is investigated using X-ray diffraction techniques, and compared with its stability constrain under high-temperature annealing. Irradiation with 63MeV protons is found to introduce no significant microdefects into the SiGe thin films, regardless of starting stability condition of the SiGe film, and thus does not appear to be an issue for the use of SiGe HBT technology in emerging space systems. The strain relaxation of SiGe thin film under thermal annealing, however, is sensitive to the composition and thickness of the as-grown samples, as expected, with the subsequent lattice relaxation of the unstable samples occurring at a much higher rate than that of metastable samples. [Copyright &y& Elsevier]