硅纳米管和纳米线场效应晶体管的模拟和比较

Simulation and Comparison of Silicon Nanotube and Nanowire Field Effect Transistors

从硅纳米管和纳米线场效应晶体管的结构出发,先用Silvaco公司的TCAD仿真软件模拟出硅纳米管和纳米线的电势分布,然后根据电势分布依次求出两种器件的有效哈密顿量、非平衡格林函数及自能函数和电子浓度,再从电子浓度推导出电流密度与电压方程,并对其进行了分析比较。仿真结果显示,在沟道横截面积相同的情况下,纳米管器件的阈值电压比纳米线器件的高,且随管内外径之差的增加而减小。栅压比较大的情况下,在饱和区纳米管器件比纳米线器件能提供更大的驱动电流。两者在亚阈值区域表现相似,亚阈值摆幅分别为58和57 mV/dec。纳米管器件的饱和电压比纳米线器件的略小,在饱和区纳米管器件的电流更加平直,短沟道效应更不明显。

The TCAD simulation software of Silvaco Inc. was used to simulate the potential distri- bution of the silicon nanotube and nanowire field effect transistors based on their structures. Then the effective Hamiltonian, the amount of non-equilibrium Green＇s function, self energy function and electron concentration of the two devices were derived from the potential distribu- tion. Besides that the current density and voltage equation was calculated and analyzed based on the electron concentration. The simulation results of the gate-all-around nanowire FET （GAA NWFET） and nanotube architecture-based FET （NTFET） were compared. The results show that the threshold voltage of the NTFET is larger than that of the NWFET with the same cross- sectional area of the channel, while the threshold voltage of the former reduces when the diffe- rence of the inner diameter and the outer diameter increases. Compared with the NWFET, the NTFET can provide a larger driving current at the saturation region when the gate voltage is large enough. In the subthreshold region, the performance of the NTFET is similar to that of the NW- FET, and their subthreshold swings are 58 and 57 mV/dec, respectively. The saturation voltage of the nanotube devices is smaller than that of the nanowire devices. The current is straighter in the saturation region for nanotube devices, which indicates that its short channel effect