Mitigation of transient radiation effects in advanced silicon-germanium technologies

Abstract

The need for flexible, low-cost electronics in extreme environment applications has brought silicon-germanium (SiGe) technologies into the spotlight, but the viable long-term capability of these semiconductor platforms in radiation-intense environments remains largely unexplored. Conventional design methodologies for radiation-hardened electronics rely on multiple system redundancies and metallic shielding, but these solutions come at severe size, weight, and cost penalties. The objective of this thesis is to explore the mechanisms of transient phenomena within bulk SiGe HBTs and develop novel techniques for mitigating radiation-induced damage within these silicon-based platforms. Heavy-ion broad beam and pulsed-laser two-photon absorption (TPA) testing are leveraged to characterize the transient response of SiGe devices and circuits. The inverse-mode operating regime is presented as a potential method for reducing single-event sensitivities within SiGe-based, bipolar logic. Complementary (npn + pnp) SiGe BiCMOS platforms are shown to exhibit an improved radiation response due to the enhanced electrical isolation provided by pnp SiGe HBTs. In addition, this work will assess the efficacy of mixed-mode simulation techniques with respect to the radiation-induced transient response of SiGe-based RF circuits as well as investigate the impact of semiconductor scaling on the radiation tolerance of current and future SiGe technologies.