Design and analysis of high-k wrapped underlap induced GaN multi-channel GAA nanosheet FET for enhanced performance with cut-off frequency in THz range

A multi-channel Gallium Nitride (GaN) based Gate-All-Around (GAA) Nanosheet Field Effect Transistor (NS FET) having 2 nm gate underlap wrapping of high-k dielectric spacer are designed, explored and analysed for inclusion in future wireless application systems. The integration of GaN as the channel material provides superior electron mobility and high breakdown voltage, making it extremely suitable for high-frequency applications. The inclusion of the gate underlap region effectively reduces parasitic capacitance while mitigate short channel effects due to its high-k wrapping. High dielectric gate stack is employed to enhance gate channel coupling and reduce leakage currents. Calibration is done utilizing a fabricated GaN FET and further validated by analytical threshold voltage modelling. Further, DC characterization reveals a remarkably low off-current (I_Off) of 12 × 10^-7nA/µm, a high switching ratio (I_On/I_Off) of 5.26 × 10¹⁰, subthreshold swing of 60.50mV/decade, and drain induced barrier lowering (DIBL) of 11.92mV/V that superbly outperform the IRDS2028 benchmarks of 1.5 nm technology node. The RF analysis demonstrates superior high-frequency performance with cut-off frequency reaching 8.16THz attributing to enhanced transconductance and minimized gate capacitance indicating the GaN NS FET operation in THz frequency regime. The use of multichannel in NS FET significantly boosts carrier transport efficiency and scaling compatibility exhibits enhanced drive current and reduced leakages. This validates and conforms devices' potential for integration into future RF front-end modules and beyond 5G/6G wireless systems. The combination benefits of material innovation, geometric optimization and electrostatic enhancement positioning this device as a strong candidate for post-CMOS ultra-scaled high-performance logic and RF applications in THz frequency regime.