Dynamic Performance Analysis of CNTFETs with Zinc Oxide Gate Dielectrics of Varying Thickness

This study evaluates the dynamic performance of carbon nanotube field-effect transistors (CNTFETs) incorporating zinc oxide (ZnO) as the gate dielectric material. Multi-walled carbon nanotubes (MWCNTs) were synthesized via low-pressure chemical vapor deposition (LPCVD) to form the channel, while ZnO thin films were deposited using RF sputtering at varying thicknesses (10 nm, 20 nm, 30 nm, and 40 nm). Gold (Au) was utilized for source, drain, and gate contacts due to its superior conductivity and compatibility with carbon nanotubes. Structural characterization using SEM revealed well-aligned CNT channels and robust CNT-metal contacts, ensuring minimal resistance. Electrical characterization highlighted the impact of ZnO thickness on device parameters, with the CNTFET exhibiting a threshold voltage (VTH) of 1 V for a 10 nm ZnO dielectric. The study underscores ZnO's potential as a gate dielectric material, offering a high dielectric constant and compatibility with CNTs, which enhances electrostatic control and reduces short-channel effects. Variations in ZnO thickness significantly influenced key device metrics such as current-voltage characteristics, transconductance, and power dissipation. Thinner ZnO layers (10 nm) demonstrated superior switching performance and energy efficiency, while thicker layers exhibited reduced leakage currents. These findings demonstrate that tuning ZnO gate dielectric properties can optimize CNTFET performance, paving the way for high-speed, energy-efficient nanoscale devices.