n型纳米非对称DG-TFET阈值电压特性研究

Study on Threshold Voltage Characteristics of the n-Type Nanoscale Asymmetric DG-TFET

n型纳米非对称双栅隧穿场效应晶体管(DG-TFET)速度快、功耗低,在高速低功耗领域具有很好的应用前景,但其阈值电压的表征及其模型与常规MOSFET不同。在深入研究n型纳米非对称DG-TFET的阈值特性基础上,通过求解器件不同区域电场、电势的方法,建立了n型纳米非对称DG-TFET器件阈值电压数值模型,探讨了器件材料物理参数以及漏源电压对阈值电压的影响,通过与Silvaco Atlas的仿真结果比较,验证了模型的正确性。研究表明,n型纳米非对称DG-TFET的阈值电压分别随着栅介质层介电常数的增加、硅层厚度的减薄以及源漏电压的减小而减小,而栅长对其阈值电压的影响有限。该研究对纳米非对称DG-TFET的设计、仿真及制造有一定的参考价值。

The n-type nanoscale asymmetric double gate tunneling field effect transistor （DG- TFET） has advantages in terms of higher speed and lower power consumption, and has been proposed as a substitute or complement for high speed and low power consumption applications. But the threshold voltage characteristic of the DG-TFET is very different from that of the MOSFET. Firstly, the threshold voltage characteristic of n-type nanoscale asymmetric DG-TFET was studied, and then a threshold voltage model of n-type nanoscale asymmetric DG-TFET was presented by solving the distributions of potential and electric field in different regions. By analyzing the model, the effect of device parameters and drain- source voltage on the threshold voltage was discussed. The results from the model were compared with the silvaco Atlas simulation results and it was found out that they are in excellent agreement with each other. The results show that the threshold voltage of n-type nanoscale asymmetric DG-TFET decreases when the dielectric constant of gate dielectric increases, the thickness of Si layer decreases, and the drain-source voltage decreases, respectively, and remain unchanged for a large range of the gate length. The pro- posed model can be easily used for reasonable analysis, design and fabrication of nanoscale asymmetric DG-TFET.