Simultaneously Estimating Process Variation Effect, Work Function Fluctuation, and Random Dopant Fluctuation of...

Area of Science:

• Semiconductor device physics
• Advanced materials science
• Integrated circuit design

Background:

• Sub-1-nm technology nodes require advanced transistor architectures like gate-all-around silicon nanosheet complementary field-effect transistors (GAA Si NS CFETs).
• Process variation effects (PVEs), metal gate work function fluctuation (WKF), and random dopant fluctuation (RDF) are critical sources of variability in nanoscale devices.

Purpose of the Study:

• To systematically investigate the combined impact of PVE, WKF, and RDF on the electrical characteristics of GAA Si NS CFETs.
• To analyze the sensitivity of N- and P-FETs to these variability sources and their effect on off-state leakage current and power dissipation.

Main Methods:

• Comprehensive statistical analysis of GAA Si NS CFETs at sub-1-nm technology nodes.
• Evaluation of combined PVE, WKF, and RDF effects on key electrical parameters.
• Assessment of relative fluctuation in static power dissipation.

Main Results:

• The interplay of PVE, WKF, and RDF causes significant off-state leakage current fluctuations in both N-/P-FETs.
• P-FETs exhibit higher sensitivity to variability due to parasitic conduction in the bottom nanosheet channel.
• The statistical sum of individual fluctuations overestimates combined effects by less than 50%.
• Static power dissipation shows the largest relative fluctuation (approx. 82.1%), challenging low-power applications.

Conclusions:

• Variability-aware design and fabrication process optimization are essential for GAA NS CFETs.
• Robust and reliable integrated circuits for future technology nodes depend on mitigating these fluctuation effects.
• Understanding combined variability impacts is critical for advancing semiconductor technology.