A novel stack-HfO₂ top-gate structure for improving the performance of network carbon nanotube transistor

Abstract Carbon nanotubes (CNTs) are regarded as a powerful contender to replace Si transistors after Moore's Law due to their advantages such as quasi-ballistic transport, high carrier mobility, and low power consumption. In the traditional CNT preparation process, CNTs are deposited on SiO 2 substrate and then the gate dielectric is deposited. In this structure, pinholes will appear between CNTs and dielectric layer, which will affect the gate-control and increase the gate leakage current. Therefore, in this paper, we designed a new stack-HfO 2 top-gate (STG) network CNTFET. By filling the pinholes between CNTs and dielectric layer, the contact interface condition is improved, reducing the subthreshold swing and improving I on / I off of the device. Meanwhile, through first-principles calculations, compared with the conventional structure, the interface charge transfer value of the CNT/HfO 2 interface for STG is about 5 times smaller than that of CNT/SiO 2 interface. Specifically, the mobility and SS, and I on / I off of the STG structure are 130 cm 2 /V·s, 156 mV/dec, and 107, respectively. Taking into account the above advantages, the proposed STG structure has reference value for improving the performance of CNTFET.