背栅黑磷场效应晶体管的制备及电学特性研究

发布时间：2018-01-24 18:53

  本文关键词： 黑磷 场效应晶体管 拉曼特性 输出特性 转移特性　出处：《江苏大学》2017年硕士论文　论文类型：学位论文

【摘要】：黑磷作为二维材料家族中一名新的成员,在电子器件领域具有石墨烯和过渡金属硫化物(TMDCs)所不具备的特性,如:可协调的带隙(0.3-2.0 eV)、高的载流子迁移率(1000 cm2V-1s-1)以及可观的开关比(105)。基于这些特性,利用黑磷制备的场效应晶体管器件具有优越的电学性能。然而,由于这种材料问世不久,在黑磷场效应晶体管的实际应用中仍然有一些未知领域需要进一步探索,如黑磷场效应晶体管的调控问题、作为晶体管器件在电路中的可靠性问题等。本论文将详细介绍黑磷场效应晶体管的声子散射和电学特性,讨论内应力对黑磷场效应晶体管性能的影响,探究黑磷场效应晶体管的击穿行为以及在大气环境下的稳定性。黑磷薄膜的样品制备采用的是机械剥离法,衬底的制备基于反应离子刻蚀(RIE)技术,在衬底上预先制备好TiW/Au电极,最后将黑磷薄膜转移到衬底上完成晶体管的制备。此方法避免了在黑磷薄膜上沉积电极过程中引入的污染,可以确保黑磷的最佳性能。利用拉曼光谱仪和半自动探针台对基于上述方法制备的300 nm栅介质的黑磷场效应晶体管进行了测试,黑磷的Ag1、B2g和Ag2三个拉曼特征峰明显,没有其他明显的缺陷峰,表明黑磷结构完整,具有最原始的特性。电学测试结果显示晶体管的输出曲线呈现线性关系,栅压可以有效地协调输出特性;晶体管的转移特性表明,黑磷场效应晶体管中为空穴作为主要载流子的双极性特性,主要表现为p型特性。RIE技术在SiO2/Si衬底上加工出的方孔可以对黑磷薄膜进行悬置,此方法有效地向晶体管中引入张应力,拉曼光谱仪显示方孔内部的黑磷薄膜与孔外部分相比Ag1、B2g和Ag2峰都发生了不同程度的红移,Ag1峰对张应力最为敏感。随后测试了该器件的电学特性,内应力对输出特性影响不大;由晶体管的转移特性计算的到载流子迁移率达到347.5 cm2V-1s-1,张应力可以在一定程度上提高晶体管的载流子迁移率。悬置的方法可以有效地协调黑磷场效应晶体管的性能,但薄的栅介质容易使晶体管发生击穿。当晶体管被击穿后,电学特性发生了质变,器件不具有晶体管的特性,行成了类肖特基二极管。器件的输出特性在不同栅压下呈相互平行的直线,出现了漏电现象,转移特性显示器件为单向导通状态。分别对同一个黑磷场效应晶体管在制备时和在空气中暴露一个月后的性能进行了测试,利用光镜可以观察到在黑磷表面形成“水滴”状物质,黑磷厚度变薄。在空气中暴露后黑磷的三个拉曼特征峰都发生了蓝移。晶体管的电阻变大,开关比和载流子迁移率均变小。
[Abstract]:As a new member of the two-dimensional material family, black phosphorus has some properties which graphene and transition metal sulfide (TMDCs) do not have in the field of electronic devices. For example: detachable bandgap of 0.3-2.0 EV, high carrier mobility of 1000 cm2V-1s-1) and considerable switching ratio of 105g. Based on these characteristics. Field-effect transistors fabricated with black phosphorous have excellent electrical properties. However, due to the recent advent of this material. In the practical application of black phosphorus field effect transistor, there are still some unknown fields that need to be further explored, such as the regulation of black phosphorus field effect transistor. In this paper, the phonon scattering and electrical properties of black phosphorus field effect transistor are introduced in detail, and the influence of internal stress on the performance of black phosphorus field effect transistor is discussed. To investigate the breakdown behavior of black phosphorus FET and its stability in atmospheric environment, the sample of black phosphorus thin film was prepared by mechanical stripping, and the substrate was prepared by reactive ion etching (rie) technique. The TiW/Au electrode is prepared on the substrate and the black phosphorus film is transferred to the substrate to prepare the transistor. This method avoids the pollution caused by the deposition of the electrode on the black phosphorus film. The optimal performance of black phosphorus can be ensured. The black phosphorus field effect transistors with 300nm gate dielectric prepared by the above method have been tested by Raman spectrometer and semi-automatic probe station. The black phosphorus Ag1 has been tested. The Raman characteristic peaks of B2g and Ag2 are obvious, but there are no other obvious defects, which indicates that the black phosphorus has the most original characteristic and the structure of black phosphorus is intact. The electrical test results show that the output curves of the transistors show a linear relationship. The gate voltage can effectively coordinate the output characteristics; The transfer characteristics of the transistors show that the holes are the main carriers in the black phosphorus field effect transistors. The main performance of this method is that the square hole fabricated by rie on SiO2/Si substrate can mount the black phosphorus film. This method can effectively introduce tensile stress into the transistor. Raman spectrometer showed that the black phosphorus films in the square pore had different red shifts compared with the outside part of the black phosphorus films in the Ag _ (1) O _ (2) g and Ag2 peaks. The Ag1 peak is the most sensitive to the tensile stress. Then the electrical properties of the device are tested and the internal stress has little effect on the output characteristics. The carrier mobility calculated from the transistors' transfer characteristics is 347.5 cm2V-1s-1. The tensile stress can improve the carrier mobility of the transistor to a certain extent, and the mounting method can effectively coordinate the performance of the black phosphorus field effect transistor. However, the thin gate dielectric makes the transistor breakdown easily. When the transistor is broken down, the electrical characteristics of the device changes qualitatively, and the device does not have the characteristics of the transistor. The output characteristics of the device are parallel to each other under different gate voltages, resulting in leakage. The transfer characteristics show that the device is in a single-pass state. The performance of the same black phosphorus field effect transistor was tested during preparation and after exposure to air for one month. Using the light microscope, we can observe the formation of "water droplets" on the surface of black phosphorus, the thickness of black phosphorus becomes thinner. After exposure to air, the three Raman characteristic peaks of black phosphorus are blue shifted and the resistances of transistors become larger. The switching ratio and carrier mobility become smaller.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN386
，

本文编号：1460764