异步对称双栅InGaZnO薄膜晶体管表面电势的解析模型  

Surface potential model for amorphous InGaZnO thin-film transistors with independent symmetric double-gate

作　　者：何伊妮 邓联文[1,2] 甄丽营 覃婷 廖聪维[1] 罗衡[1,2] 黄生祥[1] HE Yini;DENG Lianwen;ZHEN Liying;QIN Ting;LIAO Congwei;LUO Heng;HUANG Shengxiang(School of Physics and Electronics,Central South University,Changsha 410083,China;Engineering Technology Research Center in Novel Chip Inductance and Advanced Manufacturing Equipment of Hunan Province,Huaihua 419600,China)

机构地区：[1]中南大学物理与电子学院,湖南长沙410083 [2]湖南省新型片式电感及先进制造装备工程技术研究中心,湖南怀化419600

出　　处：《中南大学学报（自然科学版）》2020年第9期2480-2488,共9页Journal of Central South University:Science and Technology

基　　金：国家重点研发计划项目(2017YFA0204600);中南大学中央高校基本科研业务资助项目(2019zzts424)。

摘　　要：针对异步对称双栅结构的氧化铟镓锌(InGaZnO)薄膜晶体管(thin film transistors,TFTs),求解泊松方程,并根据载流子在亚阈区、导通区的不同分布特点,在亚阈区引入等效平带电压的概念,在导通区运用Lambert W函数近似,建立异步对称双栅InGaZnO TFT表面电势解析模型。该模型的拟合参数只有2个,能够较好地反映介电层厚度、沟道电压等参数对电势的影响。基于所建模型及TCAD分析,研究InGaZnO层厚度、栅介质层厚度以及缺陷态密度等物理量对独立栅控双栅晶体管表面电势的影响。研究结果表明:在亚阈区,表面电势随着底栅电压增大呈近似线性增大,且在顶栅电压调制作用下平移;在导通区,表面电势随着底栅电压的增加逐步饱和,且电势值与顶栅调制电压作用相关度小。表面电势的解析模型与TCAD数值计算结果对比,具有较高的吻合度;在不同缺陷态密度分布情况下,电势模型的计算值与TCAD分析值相对误差均小于10%。本研究成果有利于了解双栅InGaZnO TFT的导通机制,可用于InGaZnO TFT的器件建模及相关集成电路设计。An analytical surface potential model for the independent symmetric double-gate InGaZnO TFTs(thin film transistors)was presented.The Poisson equation was solved according to the different carrier density distributions in the subthreshold and conduction region.In the subthreshold region,the concept of equivalent flat band voltage was introduced,and in the conduction region,the approximated Lambert W function was applied to develop the analytical surface potential model for the amorphous InGaZnO thin-film transistors with independent symmetric double-gate.Furthermore,the effects of the different oxide thickness,the active layer thickness and the density of defect states were discussed.The results show that,in the subthreshold region,the surface potential increases approximately linearly with the increase of the bottom grid voltage,the surface potential shifts during the top-gate voltage modulation.In the conduction region,the surface potential has few correlation with the top-gate voltage.The present potential model shows excellent agreement with the simulation values.In the case of different densities of state distribution,the relative error of the calculation model and the TCAD analysis value is less than 10%.The result is helpful to understand the conduction mechanism of the InGaZnO TFTs,and is useful for the InGaZnO TFT device simulation and the related integrated circuit design.

关 键 词：双栅薄膜晶体管 表面势 解析模型 铟镓锌氧化物 

分 类 号：O47[理学—半导体物理]