一种基于双栅材料的单极性类金属氧化物半导体碳纳米管场效应管设计方法

Dual-gate-material-based device design for unipolar metal oxide semiconductor-like carbon nanotube field effect transistors

由于导电沟道-源/漏电极界面处可能发生的载流子带间隧穿,传统类金属氧化物半导体(MOS)碳纳米管场效应管呈现双极性传输特性,极大影响了器件性能的提高及其在电路中的应用.为获得具有理想单极性传输特性的类MOS碳纳米管场效应管,本文提出了一种基于双栅材料的器件设计方法.模拟结果表明,通过合理选取调节电极材料,在不影响器件亚阈值斜率的同时,该设计方法不仅能使开关电流比增大6—9个数量级,有效调节阈值范围,而且能有效消除传统类MOS碳纳米管场效应管的双极性传输特性.进一步研究表明,该设计所获得的器件性能提高与调节电极材料的选取密切相关,同时量子电容对其亚阈值斜率、传输极性也有一定影响.

Due to carrier band-to-band tunneling（BTBT） through channel-source /drain contacts,traditional MOS（metal oxide semiconductor）-like carbon nanotube field effect transistors（CNFETs） suffer from quasi-ambipolar transport property,leaving much negative impacts on device performance and its application in circuits.To suppress such quasi-ambipolar behavior,a novel device design based on dual-gate-material device structure is proposed.The modeling results show that,with proper choice of tuning gate material,this device design can increase the ON-OFF current ratio by 6—9 orders of magnitude,tune the threshold region effectively and keep the sub-threshold slope immune from it.In addition,the quasi-ambipolar transport characteristic of C-CNFETs can be suppressed effectively using such novel device design.Further study reveals that the performance of the proposed design depends highly on the choice of tuning gate material,and the quantum capacitance in CNFETs has great effect on not only its subthreshold slope but also its transport polarity.