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为研究以单壁碳纳米管(CNT)作沟道的场效应晶体管(FET)的输运特性,采用非平衡格林函数(NEGF)理论,构建了CNTFET的电子输运模型,该方法摒弃粗糙的连续体模型,可实现CNTFET输运性质与手性指数的直接对接。以(17,0)锯齿型管为例,数值计算了CNTFET输出特性、转移特性、跨导、亚阈值摆幅、开关态电流比等电学特性;在等效栅氧化层厚度相同的情况下,对比了采用不同栅介质材料时上述电学特性在数值上的差异,发现随栅介质介电常数的增加,漏感应势垒降低效应变得显著,这不但导致开态时从源注入到漏的电子浓度增加、电流增大,也导致关态电流增大,开关态的电流比减少。研究还发现在通常的栅源和漏源电压下,沟道中出现热电子。
In order to study the transport characteristics of field-effect transistors (FETs) with single-walled carbon nanotubes (CNTs) as the channel, an electron transport model of CNTFET was constructed by using the non-equilibrium Green’s function (NEGF) theory. The continuum model enables direct docking of CNTFET transport properties with chiral index. Taking the (17, 17) serrated tube as an example, the electrical characteristics of CNTFET such as output characteristic, transfer characteristic, transconductance, subthreshold swing and on-off current ratio are calculated numerically. When equivalent gate oxide thickness is the same, Comparing the numerical differences of the above electrical properties when using different gate dielectric materials, it is found that with the increase of the dielectric constant of the gate dielectric, the reduction effect of the leakage induced barrier becomes significant, which not only leads to the electron injection from the source to the drain at the on state Increasing the concentration, the current increases, also led to off-state current increases, the switching state of the current ratio decreases. The study also found that at common gate and drain-source voltages, hot electrons appear in the channel.