Performance Optimization of Channel Length Modulated Vertical Nanowire Tunnel Field Effect Transistors for High Frequency and Radio Frequency Applications
摘要
In this work, the length of the channel for vertical nanowire tunnel FET is modulated for performance enhancement and the channel length modulated (CLM) vertical nanowire tunnel field effect transistor (VNW-TFET) is proposed. As the channel length modulation effects quantization, our goal is to reduce its impact on gate capacitance, which can change the device’s performance. To determine the device’s performance, other factors are taken into consideration, such as the device’s threshold voltage (Vt), sub-threshold swing (SS), on-off current ratio (ION/IOFF), and drain induced barrier lowering (DIBL). It is discovered that the CLM-VNW-TFET performs better than the traditional VNW-TFET when the channel length is 20 nm. Later on, the gate metal work function (ϕMG) of the proposed device CLM-VNW-TFET is varied from 3.9 to 4.5eV and the impact of this variation is studied. The work-function variation effects of channel length modulated vertical nanowire tunnel FET are discussed for the first time. After investigation, it is found that the device CLM-VNW-TFET with ϕMG of 3.9 eV produces best ON-current (ION), OFF-current (IOFF) and other parameters. The device exhibits ION of 3.52 × 10–6 A/µm, IOFF of 7.30 × 10–17 A/µm and high ION/IOFF as 4.83 × 1010.