The Impact of Technology Scaling on the Single-Event Transient Response of SiGe HBTs

Abstract

The impact of semiconductor process scaling on the overall transient response of SiGe BiCMOS platforms is investigated. Pulsed-laser two-photon absorption (TPA) and heavyion broad-beam testing of SiGe HBT device and digital test structures across several generations of SiGe technologies are utilized to investigate the potential impacts of semiconductor process scaling (e.g., lateral/vertical scaling, changes in doping, Ge content, etc.) on the overall transient shape, magnitude, and duration. Technology scaling is shown to increase the single-event effect (SEE) sensitivity of SiGe HBTs (i.e., elevated collected charge, where 1st Gen. Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> <; 3rd Gen. Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> <; 4th Gen. Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> ). Modern third-generation and fourth-generation devices under a forward-active bias (i.e., forward-biased EB junction, reversebiased CB junction) exhibit a large diffusive transient component between the emitter and collector terminals, driving an elevation in collected charge. 3-D TCAD modeling is utilized to understand the fundamental transient mechanisms and assess the primary scaling factors affecting SEE sensitivity. Ion-strike simulations show that bulk traps can substantially enhance the charge collection mechanisms within these devices. These results suggest that SiGe technology scaling may have a strong impact on the radiation-induced transient response of SiGe HBTs, with future SiGe technology generations potentially exhibiting increased sensitivities to single-event effects.