摘要
石墨烯场效应晶体管的研究对于摩尔定律的延续具有非常重要的意义.近年来,大面积、高质量石墨烯薄膜制备技术的快速发展,进一步推动了基于石墨烯材料的新型电子器件的研究,引起了集成电路领域研究人员的广泛关注.本文所制备的石墨烯场效应晶体管以ITO为栅电极,Ta_2O_5为栅绝缘层,石墨烯为有源层,Ti/Au双层金属为源漏电极.电学特性测试与分析结果表明,石墨烯与源漏电极形成了良好的欧姆接触.室温下,石墨烯场效应晶体管展示了其特有的双极性特征,空穴迁移率约为2272 cm2/(V s),电流开关比约为6.2.转移特性曲线中出现了明显的滞回现象,且随着栅压扫描范围的增大而越发显著.同时研究了温度对石墨烯场效应晶体管性能的影响,随着温度的升高,狄拉克点电压逐渐向零点方向偏移,滞回现象愈加明显.当温度为75℃时,空穴迁移率与电流开关达到最佳.
Nowadays, integrated circuit design and manufacturing level is one of important symbols to evaluate the industrial development level of a country. Silicon-based metal oxide semiconductor field effect transistor has an important application in large-scale integrated circuit, and its special size has reached 14 nm. However, further miniaturization in reaching the silicon physical limits of 10 nm channel length. Graphene is one of the most promising materials to replace silicon. Due to its outstanding performance such as ultrafast carrier mobility, excellent mechanical strength and high transparency invisible light region, graphene is regarded as one of the vital next generation electronic materials. In recent years, the rapid development of the preparation technology of large area and high quality graphene has further promoted the research of new electronic devices based on graphene, which has attracted wide attention of researchers in the field of integrated circuit. Graphene field effect transistor has fast response rate and high cut-off frequency, whose feature size can continue to narrow. Therefore, the study of graphene field effect transistors has very important significance for the cominuation of Moore＇s law. Currently, SiO2 is generally used to the gate insulating layer of graphene field effect transistors. The dielectric constant value of SiO2 is lower, which leads to higher power consumption of the device. When the thickness of the SiO2 gate insulating layer is reduced to a certain degree, the device is easy to breakdown. However, when the semiconductor materials with high dielectric constant （Ta2Os, TiO2, A1203, etc.） as the gate insulating layer, the device can obtain higher mobility in the operating voltage as low as possible. This is an effective way to solve the high power consumption of the device. Although graphene field effect transistors have made some progress in the preparation and performance, the existing field effect transistors based on graphene have no obvious advantage in cartier mobility and current on/off ratio. Accordingly, the research of graphene field effect transistor will be the main direction of the field of integrated circuit in the future. In this paper, the graphene field effect transistors use ITO as the gate electrode, Ta2O5 as the gate insulating layer, graphene as the active layer, Ti/Au double-layer metal as the source/drain electrodes. The results of electrical properties measurements and analyses show that the graphene strip is in good ohm contact with source/drain electrodes. At room temperature, graphene field effect transistors exhibit an unique bipolar characteristic. The mobility for hole carrier is about 2272 cm2/（V s） and the current on/off ratio is about 6.2. The hysteresis phenomenon in the transfer characteristic curve is observed, which becomes more obvious with the increase of gate voltage. Meanwhile, the effect of the temperature on the characteristic of the graphene field effect transistor is studied. With the increase of temperature, the Dirac point voltage gradually shifts to zero point, and the hysteresis phenomenon becomes more and more obvious. The mobility for hole carrier and the current on/off ratio achieve optimum when the temperature is 75℃. The content and conclusions of above may provide a reference for further research of graphene field effect transistors.
出处
《科学通报》
EI
CAS
CSCD
北大核心
2017年第14期1520-1526,共7页
Chinese Science Bulletin
基金
河北省在读研究生创新资助项目(220056)
河北省自然科学基金(F2012202075)资助
关键词
石墨烯场效应晶体管
迁移率
电流开关比
滞回现象
温度
graphene field effect transistors, mobility, current on/off ratio, hysteresis phenomenon, temperature
作者简介
联系人，E-mail：wangwei@hebut．edu．cn
