基于GaN纳米线铁电场效应晶体管及相关电性能

发布时间：2018-03-27 21:34

本文选题：铁电存储器　切入点：铁电场效应晶体管　出处：《华南理工大学》2015年硕士论文

【摘要】：铁电存储器因具有非易失、低功耗、高读写速度、高存储密度、长寿命和抗辐射等优点,被认为是下一代最具潜力的存储器之一。其中由铁电场效应晶体管构成存储单元的铁电存储器,还具有单元结构简单、非破坏性读出、存储密度更高和与集成电路工艺兼容等更多优点,得到了研究者的广泛关注。然而,目前在基于纳米线的铁电场效应晶体管研究过程中,还有许多需要解决的科学问题,其中如何采用微纳加工技术组装纳电子器件并进行精确表征与评价,是研制基于纳米线铁电场效应晶体管亟待解决的首要问题。本论文创新性地联合光刻技术与聚焦离子束技术成功组装了基于Ga N纳米线的铁电场效应晶体管,器件表现出良好的性能。具体工作和结论如下:1、采用CVD法成功制备了适于晶体管导电沟道组装使用的、高质量的Ga N纳米线,其生长过程符合以Au纳米颗粒为催化剂的汽-液-固(VLS)生长机制。分别用XRD、SEM、EDS、TEM对所制备的纳米线进行了形貌与晶体结构表征,结果表明所制备的纳米线表面平直光滑,长度为几十到几百微米,直径分布在100-200 nm之间,为高纯度的六方纤锌矿结构的Ga N晶体,其生长方向为[100]晶向。2、基于磁控溅射的方法制备了PZT铁电薄膜,获得了适于晶体管组装用的PZT/Pt/Ti/Si O2/Si的层状背栅体系结构。分别用XRD、SEM、EDS、Raman、铁电分析仪对其进行了表征,结果表明薄膜表面平整光滑,没有大的颗粒堆积和裂纹,晶粒直径在2-5μm的范围内。薄膜的厚度均匀,膜厚大约为500 nm。薄膜为高纯度的四方相和三方相混合的多晶钙钛矿结构,铁电性能优越,低压下就能形成比较完整的电滞回线。3、联合光刻技术与聚焦离子束(FIB)技术成功组装了以Ga N纳米线为导电沟道、PZT/Pt/Ti/Si O2/Si为背栅结构的铁电场效应晶体管。晶体管的输出和转移特性结果表明组装的晶体管为n型耗尽模式的场效应晶体管,具有优越的存储性能和电性能,数据存储窗口高达5 V,零栅压时的开关电流比高达103,亚阈值摆幅S很小为0.93 V/decade,峰值跨导gm为1.7μS,Ga N纳米线沟道中的场效应载流子迁移率μ大约为16.4 cm2/V·s。4、测试了Pt/SBT/Hf Ta O/Si铁电电容与温度和辐照相关的电性能,并对其机理进行了分析。为纳米线铁电场效应晶体管与温度和辐照相关可靠性研究提供了实验基础和理论储备,有利于铁电存储器在特殊领域的应用和推广。以半导体纳米线为导电沟道的新型结构铁电场效应晶体管具有比如可在极低的电压下操作、极高的读写速度等优越的性能,本文的结果为基于纳米线的非易失性存储器潜在应用提供了实验基础和理论指导。
[Abstract]:Ferroelectric memory has the advantages of non-volatile, low power consumption, high read and write speed, high storage density, long life and radiation resistance, etc. It is considered to be one of the most promising memories of the next generation. Ferroelectric memory, which consists of ferroelectric field effect transistors, also has a simple structure and non-destructive readout. More advantages, such as higher storage density and compatibility with integrated circuit processes, have attracted extensive attention of researchers. However, there are still many scientific problems to be solved in the research of ferroelectric field effect transistors based on nanowires. Among them, how to use micro-nano fabrication technology to assemble nanoelectronic devices and to carry out accurate characterization and evaluation, Ferroelectric field effect transistors based on nanowires are the most important problems to be solved. In this thesis, the ferroelectric field effect transistors based on gan nanowires have been successfully assembled by combining photolithography with focused ion beam technology. The specific work and conclusions are as follows: 1. High quality gan nanowires suitable for conducting channel assembly of transistors have been successfully fabricated by CVD method. The growth process is consistent with the VLS growth mechanism of au nanoparticles. The morphology and crystal structure of the prepared nanowires were characterized by XRDX SEMN EDS- TEM. The results show that the surface of the prepared nanowires is straight and smooth. PZT ferroelectric thin films were prepared by magnetron sputtering based on the high purity hexagonal wurtzite gan crystal with a length of several to several hundred microns and diameters ranging from 100 to 200 nm. The layered back gate structure of PZT/Pt/Ti/Si O2/Si for transistor assembly was obtained. The structure was characterized by a ferroelectric analyzer. The results showed that the surface of the thin film was smooth and there were no large particles stacking and cracks. The grain diameter is in the range of 2-5 渭 m. The thickness of the film is uniform, and the thickness of the film is about 500 nm. The thin film is a polycrystalline perovskite structure of high purity tetragonal phase and rhombohedral phase, and has excellent ferroelectric properties. A complete hysteresis loop. 3 can be formed at low voltage. The ferroelectric field effect transistor with gan nanowires as conducting channel PZT / PT / Ti / Si O2/Si as back gate structure has been successfully assembled by combining photolithography and focusing ion beam technique. The output and transfer characteristics show that the assembled transistors are field effect transistors with n-type depletion mode. With superior storage and electrical performance, The data storage window is up to 5 V, the switching current ratio is as high as 103 at zero gate voltage, the sub-threshold swing S is very small, and the peak transconductance gm is 1.7 渭 SGN nanowire channel. The field effect carrier mobility 渭 is about 16.4 cm2/V s.4. The Pt/SBT/Hf Ta O/Si has been tested. Ferroelectric capacitance electrical properties related to temperature and irradiation, The mechanism is analyzed, which provides an experimental basis and theoretical reserve for the reliability study of nanowire ferroelectric field effect transistors related to temperature and irradiation. It is beneficial to the application and popularization of ferroelectric memory in special fields. The novel ferroelectric field effect transistors with semiconductor nanowires as conducting channels have excellent properties such as operating at very low voltage, high reading and writing speed, etc. The results of this paper provide experimental basis and theoretical guidance for the potential application of nonvolatile memory based on nanowires.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN386;O614.371

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