Single-Event Transients in SiGe HBTs Induced by Pulsed X-Ray Microbeam

Abstract

This article presents an experimental study of single-event transients (SETs) induced by pulsed X-rays in SiGe heterojunction bipolar transistors (HBTs). Device-level transient data and circuit-level upset data from pulsed X-rays are analyzed and compared to those of heavy-ions. 3-D TCAD modeling is utilized to understand the source of the differences in the transients. The transient peak from the ion-shunt effect is not present in pulsed X-ray transients due to its large spot size and slow pulse transition, both of which lead to lower peak carrier densities. The diffusion “tail,” typically present in transients measured from SiGe HBTs, also differs between the two sources. The charge collection of X-ray has a linear correlation with surface linear energy transfer (LET) across the photon energies of 8–12 keV. For a similar surface LET, the impinging heavy-ion pushes the subcollector-substrate junction boundaries of the SiGe HBT deeper, resulting in higher charge collection. Single-event upset (SEU) screening of shift-registers shows that X-ray can detect device sensitive nodes smaller than the beam.