Characterization of the CMOS FinFET structure on single-event effects – basic charge collection mechanisms and soft error modes

Abstract

With technology scaling at 22 nm and beyond, the semiconductor industry has successfully transitioned to 3D multi-gate transistors (i.e., FinFETs) due to the excellent FinFET gate control and reduced short channel effects over planar CMOS devices. For the radiation-induced effects community, however, the change from planar transistor to FinFET structure introduces new considerations for single-event effects (SEE) in FinFET based circuits. The FinFET structure impacts the single-event (SE) sensitive area, charge deposition/collection processes after an ion strike, and the resulting SE responses of FinFETs. In addition, while angular SEE-induced mechanisms and soft error modes in planar technologies are well understood, the structure of FinFETs introduces unique geometric and orientation dependences for angular SE mechanisms and experimentally observed SE responses of FinFET designs.

In this work, the impact of the CMOS FinFET structure on SE mechanisms and SE responses of bulk FinFET technologies is fully characterized using 3D TCAD simulations and heavy-ion broadbeam measurements of 14/16nm bulk FinFET circuits. A set of upset criteria based on circuit characteristic switching time frame is also developed and used to bridge transistor-level TCAD simulations to circuit-level SE cross section responses of advanced (fast and small) digital circuits. Additionally, four angular upset mechanisms have been discovered and presented in this work. Angular SE analysis of bulk FinFET designs is important because of its impact on error rates. Insights of this work advance the understanding of the overall angular upset behavior of bulk FinFETs and are also applicable to other advanced technologies (e.g., 32nm PDSOI, 22nm FDSOI, 7nm bulk FinFETs, and nanowires). The findings of this research also enable risk reduction in the development of radiation hardening by design techniques used in terrestrial, defense, and space FinFET-based applications.