介质中双缺陷电荷对碳纳米管场效应晶体管量子输运特性的影响  

Quantum Transport in a Carbon Nanotube Transistor:Influence of Two Charged Defects in Dielectric

作　　者：魏志超 王能平 WEI Zhichao;WANG Nengping(Department of Microelectronic Science and Engineering,School of Physical Science and Technology,Ningbo University,Ningbo,Zhejiang 315211,China)

机构地区：[1]宁波大学物理科学与技术学院微电子科学与工程系,浙江宁波315211

出　　处：《计算物理》2020年第3期352-364,共13页Chinese Journal of Computational Physics

基　　金：国家自然科学基金(61176081)资助项目。

摘　　要：用非平衡格林函数理论和紧束缚模型近似计算长沟道弹道输运p型碳纳米管场效应管中电流强度.研究当场效应管介质(SiO2)中存在两个带电缺陷时,载流子散射所引起的电流强度减小和栅极阈值电压偏移量与缺陷位置的关系.介质中两个缺陷所带电荷Q1=Q2=+e(-e为电子电荷),都靠近源极或者都靠近漏极,或者一个电荷靠近源极另一个电荷靠近漏极.在工作状态下,所引起的电流强度相对减小比介质中只存在单个正电荷Q=+e且靠近源极(或漏极)时所引起的电流强度相对减小大得多.如果两个正电荷都在沟道中央附近,随着两个电荷的轴向距离减小,栅极阈值电压偏移的绝对值明显增加.栅极阈值电压偏移可达到-0.35 V.Nonequilibrium Greens function method in a tight-binding approximation is used to calculate current through a carbon nanotube field-effect transistor(CNFET)with cylindrical gate electrode.Two individual defects in gate oxide(SiO2)of a long channel p-type CNFET is investigated.It is found that the relative current reduction and the threshold voltage shift caused by two charged defects depend sensitively on positions of the charged defects.If the charges Q1=Q2=+e(where-e is electron charge)are both close to one of the two leads,or one is close to the source lead and the other is close to the drain lead,the relative current reduction in onstate is much greater than that due to a single positive charge Q=+e located close to one of the two leads.In this case,the threshold voltage shift due to two charges is negligible.If two positive charges are both around center of the channel,the relative current reduction in on-state caused by two charges is significantly greater than that caused by a single positive charge near center of the channel.Furthermore,the negative shift of threshold gate voltage increases with decreasing distance between two charges.And a great threshold voltage shift of-0.35 V may be caused.

关 键 词：非平衡格林函数 碳纳米管 场效应管 随机电报信号杂音 

分 类 号：O469[理学—凝聚态物理]