Low Power Switching Characteristics of CNT Field Effect Transistor Device with Al-Doped ZrHfO₂ Gate Dielectric

Abstract

In this report, we demonstrated a reliable switching effect of carbon nanotube (CNT) field-effect transistor (FET) devices integrated with 99% semiconducting CNT as a channel and high-k oxide as the dielectric. CNT FET devices with high-k oxides of Al-ZrHfO2 and Al2O3 were electrically characterized and compared. There was no considerable hysteresis in the Al2O3-based CNT FET device. The Al-ZrHfO2 with a tetragonal phase-based high dielectric constant (~47), designed by an atomic layer deposition process, showed a reliable switching effect as well as low operation voltage (<±3 V). Charge trapping/detrapping process via oxygen vacancy-related defects of Al-ZrHfO2 was proposed as a primary mechanism to explain a current change of a counterclockwise direction and threshold voltage (Vth) shift for transfer properties. The suggested charge trapping model within bulk oxide was experimentally proven since the hysteresis from the adsorption/desorption of gas molecules to CNT surface was negligible. Endurance characteristics of the CNT switching devices remained stable without any serious current fluctuation during a repetitive cycling test. The memory device with reliable switching properties as well as low operation power would pave a road toward next-generation memory components of portable electronic gadgets.

Numerical simulation and parametric assessment of GaN buffered trench gate MOSFET for low power applications

“…To minimise leakage current and improve gate control, it is desirable that the equivalent oxide thickness (EOT) [12] be as low as possible. For EOT to be a minimum, gate stacking is used where a high‐K dielectric material HfO 2 [13] is used to complement SiO 2 as a gate stacking material. Improved gate control is achieved by increasing gate oxide capacitance ( C ox ) [14].…”