The Effect of Low-Temperature Annealing on the Electrical Characteristics of Carbon Nanotube Network Field-Effect Transistors

Carbon nanotube network field-effect transistors (CNT-FETs) have been recognized as strong candidates for post-Si era electronics due to their higher speed, lower power consumption, and high sensing capabilities. In this study, CNT-FET structures were fabricated on heavily doped Si substrates with an oxide layer. To investigate the effect of low-temperature annealing on the electrical properties, the transistors were annealed at 120 °C for 1 h, the transfer and output characteristics of the transistors were measured, and the key electrical parameters, such as field-effect mobility, effective mobility, threshold voltage, interface states, transconductance, drain conductance, resistance, and hysteresis gap values were obtained. A series of device parameter evaluation results showed that low-temperature annealing treatment in air can effectively improve the on-state current, increase the mobility, and reduce the device threshold voltage and subthreshold swing. In addition, a large decrease in contact resistance, from 1.9 MΩ to 12.3 kΩ, was observed after low-temperature annealing. It has been found that low-temperature annealing has a tremendous improvement effect on the electrical characteristics of CNT-FETs and should be considered during the production and design stages of CNT transistors.