Quantitative mechanism separation of single-event transients in nanosheet transistors via TCAD simulation

Area of Science:

• Semiconductor Device Physics
• Radiation Effects in Electronics

Background:

• Advanced semiconductor manufacturing employs nanosheet structures, leading to reduced dimensions and vertical stacking.
• These architectural changes introduce new challenges for single-event effect (SEE) sensitivity in integrated circuits.

Purpose of the Study:

• To systematically investigate the impact of key physical parameters on the single-event transient (SET) response of n-type nanosheet devices.
• To quantitatively differentiate the contributions of funneling and parasitic bipolar junction transistor (BJT) amplification mechanisms to SET.

Main Methods:

• Calibrated Technology Computer-Aided Design (TCAD) simulations were employed.
• Electron current integrals at source and drain cross-sections were extracted to analyze transient stages.
• The influence of gate length, number of nanosheet stacks, sheet spacing, and drain voltage was systematically evaluated.

Main Results:

• The SET response demonstrates a distinct two-stage behavior: a prompt peak and a delayed tail.
• The prompt peak is primarily driven by the funneling effect, influenced by gate length, drain voltage, and sensitive volume.
• The delayed tail is governed by parasitic BJT amplification, dependent on device structure, with nonlinear effects observed for increased stacks.

Conclusions:

• The two-stage SET mechanism provides a fundamental understanding for radiation-hardened design in gate-all-around (GAA) nanosheet devices.
• Gate length reduction impacts the peak stage's parasitic BJT effect, while increased stacks amplify the tail stage.
• Sheet spacing has a minor effect, and drain voltage primarily modulates the peak stage, not tail attenuation.