使用Y函数方法提取MoS2 FET双向扫描电学参数

Y-Function Method Applied to Extracting Bidirectional Scanned Electrical Parameters of MoS2 FETs

利用机械剥离法制备了多层背栅MoS_2场效应晶体管（FET）,通过双向栅压扫描提取了器件的转移特性曲线,并利用Y函数方法提取了器件的电学参数。结果表明,利用Y函数法提取的载流子迁移率值明显大于利用跨导法提取的载流子迁移率值。这两种提取方法的不同之处在于Y函数方法考虑了寄生电阻的影响,而跨导法则将其忽略了,这说明寄生电阻带来的影响是显著的。此外,该器件在双向扫描过程中出现了明显的回滞特性,这主要是MoS_2材料吸附外界杂质电荷造成的。无论采用跨导法还是Y函数方法,其正向扫描和反向扫描时对应的电学参数都不完全一致。这表明在分析MoS_2 FET的电学性能时,除了考虑器件的寄生电阻外,还需要考虑界面电荷的影响。

Back-gated multi-layer MoS2 field effect transistors （FETs） were fabricated with mechanical exfoliation method. The transfer characteristic curve of the device was extracted by bidirectional gate voltage scanning, and the electrical parameters of the device were extracted by using the Y-function method. The results show that the carrier mobility extracted from Y-function method is obviously higher than that extracted from transconductance method. The difference between the two extraction methods is that the Y-function method considers the influence of the parasitic resistance, while the transconductance method ignores it, indicating that the influence of parasitic resistance is significant. In addition, the hysteresis characteristic of the device was obvious during the bidirectional scanning process, which was mainly caused by the absorption of the external impurity charge in the MoS2material. For the transconductanee method and the Y-function method, the corresponding electrical parameters extracted from the forward and the reverse scanning were not completely consistent. The results show that when analyzing the electrical properties of the MoS2 FET, the effects of the interface charge as well as the influence induced by the para-sitic resistance should be considered.