栅介质材料及尺寸对薄膜晶体管性能影响研究  

Investigation on the influence of gate dielectric material and size on thin-film transistors performance

作　　者：裴智慧 秦国轩 Pei Zhihui;Qin Guoxuan(School of Microelectronics,Tianjin University,Tianjin,300072,China;Tianjin Key Lab Imaging and Sensing Microelectronic Technology,Tianjin,300072,China)

机构地区：[1]天津大学微电子学院,天津300072 [2]天津市成像与感知微电子技术重点实验室,天津300072

出　　处：《南京大学学报（自然科学版）》2019年第5期740-749,共10页Journal of Nanjing University（Natural Science）

基　　金：国家自然科学基金(61871285);天津市自然科学基金(18JCYBJC15900)

摘　　要：系统地对基于高介电常数材料HfO2和传统的介质材料SiO2这两种不同栅介质层材料的硅薄膜晶体管进行建模并对不同尺寸和温度条件下的薄膜晶体管的工作特性进行了研究.获得了不同沟道长度和沟道宽度,不同栅介质层厚度和不同温度条件下的薄膜晶体管的工作特性曲线.通过对比发现,薄膜晶体管的饱和电流与沟道长度和栅介质层厚度成反比,与沟道宽度成正比,与理论计算一致.随着温度的升高,薄膜晶体管的载流子迁移率和阈值电压都在逐渐减小,因而饱和电流值逐渐减小;在相同栅介质层尺寸和温度条件下,基于HfO2的薄膜晶体管相对于基于SiO2的薄膜晶体管具有更高的电流开关比,更低的阈值电压和更小的泄漏电流.因此,基于高介电常数栅介质材料的薄膜晶体管相对于基于SiO2的薄膜晶体管具有更好的性能.The models of silicon thin-film transistors based on two different dielectric materials which include HfO2 with high dielectric constant and conventional dielectric material SiO2,were obtained and the working characteristics of these thin-film transistors with different size and temperature conditions were systematically investigated. The working characteristics of thin-film transistors with different channel length and channel width,different gate dielectric layer thickness and different temperature conditions were obtained. By comparison,it is proved that the saturation current of the thin?film transistor is inversely proportional to the channel length and the thickness of the gate dielectric layer,and proportional to the channel width,which is consistent with the theoretical calculation. The carrier mobility and threshold voltage are gradually decreasing with temperature increasing. Therefore,the saturation current of the transistors decreases with the temperature increasing. With the same gate dielectric layer size and temperature conditions,the thin-film transistors based on HfO2 have higher current on/off ratios,lower threshold voltage and lower leakage current than the thin-film transistors based on SiO2. Therefore,a thin ? film transistor based on gate dielectric material with high dielectric constant has better performance than a thin?film transistor based on SiO2.

关 键 词：薄膜晶体管 高介电常数 栅介质材料 栅介质尺寸 

分 类 号：TP432[自动化与计算机技术]