Design and performance analysis of wrap-gate CNTFET-based ring oscillators for IoT applications

In recent years, usage of novel non-Si materials as the gate channel region in next generation of field effect transistors, including carbon nanotubes, have been in the spotlight of nanoelectronics research due to astounding carrier transport and I-V characteristics. These properties make them a highly suitable platform in modern radio frequency applications. Therefore, the aim of this work is to design and investigate the performance of current-starved and skewed ring oscillators based on ballistic carbon nanotube transistors (CNTFETs). In this work, we have utilized wrap-gate structure to have a better electrostatics control and mitigate the gate leakage current. All the CNTs in both n-type and p-type transistors have 0.9 nm diameter and an array of CNTs have been exploited in the gate region to achieve low-power and high-performance operation. The simulation results demonstrate that the proposed CNTFET-based ring oscillators have sub-100μW power consumption (P_{current-starved} = 6.011 μW, P_low-skew = 67.2 μW, and P_high-skew = 23.5 μW) along with wide frequency tuning range (f_{current-starved} = 0.202 GHz − 1.205 GHz, f_low-skew = 0.361 GHz − 2.137 GHz, and f_high-skew = 0.335 GHz − 2.38 GHz) which are suitable for internet of thing (IoT) devices operating from 100 MHz to 5.8 GHz. Finally, based on the simulation results, we have emphasized that the CNTFET-based skewed ring oscillators are suitable for high-speed purposes, while the CNTFET-based current-starved ring oscillator is recommended for low-power and high-swing applications.