基于异质双栅电极结构提高碳纳米管场效应晶体管电子输运效率  

Improvement on the electron transport efficiency of the carbon nanotube field effect transistor device by introducing heterogeneous-dual-metal-gate structure

作　　者：刘兴辉[1] 赵宏亮[1] 李天宇[1] 张仁[1] 李松杰[1] 葛春华[2] 

机构地区：[1]辽宁大学物理学院,沈阳110036 [2]辽宁大学化学院,沈阳110036

出　　处：《物理学报》2013年第14期433-440,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:21171081);辽宁省科技厅自然科学基金(批准号:20082050);辽宁省教育厅高等学校科研基金(批准号:L2010152)资助的课题~~

摘　　要：为改善碳纳米管场效应晶体管(CNTFET)器件性能,提高电子输运效率,提出了一种异质双金属栅(HDMG)电极结构CNTFET器件.通过对单金属栅(SMG)-CNTFET器件输运模型的适当修改,实现了对HDMG-CNTFET器件电子输运特性的研究.研究结果表明,对于所提出的HDMG结构器件,如果固定源端金属栅S-gate的功函数WGS使其等于本征CNT的功函数,而选取漏端金属栅D-gate的功函数WGd,使其在一定范围内小于WGS,可优化器件沟道中的电场分布,提高器件沟道电子平均输运速率;同时由于HDMG-CNTFET的D-gate对沟道电势具有调制作用,使该器件阈值电压降低,导致在相同的工作电压下,HDMG-CNTFET器件具有更大的通态电流;而D-gate对漏电压的屏蔽作用又使HDMG-CNTFET与SMG-CNTFET相比具有更好的栅控能力及减小漏极感应势垒降低效应、热电子效应和双极导电性等优点.本研究通过合理选取HDMG-CNTFET双栅电极的功函数,有效克服了现有研究中存在的改善CNTFET性能需要以减小通态电流为代价的不足,重要的是提高了器件的电子输运效率,进而可提高特征频率、减小延迟时间,有利于将CNTFET器件应用于高速/高频电路.To improve the carbon nanotube field effect transistor （CNTFET） device performance and enhance the electron transport efficiency of the device, a heterogeneous-dual-metal-gate （HDMG）-CNTFET is proposed. By appropriately modifying the transport model for single-metal-gate （SMG）-CNTFET, the electron transport properties of the HDMG-CNTFET device are investigated. The results indicate that the work function W GS of the metal gate near the source （S-gate） is fixed such that it is equal to that of the intrinsic CNT, and the work function W Gd of the metal gate near the drain （D-gate） is selected to be smaller than W GS within a certain range, the electric field distribution can be optimised and the average electron velocity in the CNTFET channel can be significantly increased; at the same time, due to the electric potential modulation by the D-gate, the device has a lower threshold voltage. When the same operating voltage is applied, HDMG-CNTFET has a larger on-state current than SMG-CNTFT; and due to the shielding effect of the drain voltage variation by D-gate, the HDMG-CNTFET device exhibits good gate-control ability and can suppress the drain-induced barrier lower effect, hot electron effect and ambipolar conduction behavior compared with SMG-CNTFET. This study, by reasonably selecting the gate electrode work function of the HDMG-CNTFET, can effectively overcome the deficiency of existing research on improving the CNTFET performance at the expense of reducing the on-current, more importantly, can improve the electron transport efficiency, thereby improving the characteristic frequency and reducing the delay time of the device, which will be of benefit to CNTFET application in high-speed/high-frequency circuit.

关 键 词：CNTFET 异质双栅 电子输运效率 双极导电性 

分 类 号：TN386[电子电信—物理电子学]