Piezoresistive sensitivity enhancement below threshold voltage in sub-5 nm node using junctionless multi-nanosheet...

Area of Science:

• Semiconductor device physics
• Materials science

Background:

• Piezoresistive sensors are crucial for pressure detection.
• Enhancing sensitivity in nanoscale transistors remains a challenge.

Purpose of the Study:

• To improve the piezoresistive sensitivity of sub-5 nm junctionless field-effect transistors (JLFETs).
• To investigate the effect of mechanical stress (MS) on multi-nanosheet (NS) channels.
• To explore device design parameters for optimized pressure sensing.

Main Methods:

• Applying uniform mechanical stress to multi-nanosheet channels in sub-5 nm JLFETs.
• Modulating channel conductivity via low gate biasing and reducing physical channel width.
• Utilizing horizontally multi-nanosheet stacking for uniform stress distribution.

Main Results:

• Achieved a maximum sensitivity enhancement of approximately 6 times in the subthreshold regime compared to the ON-state.
• Observed a further sensitivity increase of ~30.3% near the threshold voltage with multi-NS stacking.
• Demonstrated superior performance over inversion-mode devices due to reduced scattering, better thermal stability, and lower electronic noise.

Conclusions:

• Uniform mechanical stress on multi-nanosheet channels significantly boosts piezoresistive sensitivity in JLFETs.
• Tunable sensitivity in junctionless multi-channel devices offers advantages for pressure sensing applications.
• The findings pave the way for highly sensitive and stable nanoscale pressure sensors.