SnO薄膜及其双极性晶体管的性能调控

发布时间：2018-03-05 09:29

本文选题：SnO　切入点：电子束蒸发　出处：《宁波大学》2015年硕士论文　论文类型：学位论文

【摘要】：双极性薄膜晶体管可以通过改变栅极和源漏电压的极性和大小来实现空穴和电子的可控注入与输运。其可简化电路的设计和制备流程,从而大大减少相关器件、电路制造的复杂程度。近十几年以来,以氧化物半导体为沟道的薄膜晶体管具有较高的场效应迁移率、较小的亚阈值摆幅、较大的开关比、较好的透明性、可低温制备以及与硅基工艺基本兼容等诸多优点而备受关注。然而多数氧化物半导体薄膜晶体管表现为单极性(n型或p型),有关双极性氧化物半导体薄膜晶体管的报道则相对较少。双极性氧化物薄膜晶体管的实现,面临沟道材料性能优化和器件结构设计两方面的挑战。本论文采用氧化亚锡(SnO)为沟道层材料,围绕上述两个关键点展开研究。主要成果如下:(1)本研究实现了多晶SnO薄膜的结晶取向控制和拉曼特征峰。通过电子束蒸发技术分别制备了(001)和(101)结晶取向的多晶SnO薄膜。实验表明,SnO薄膜中化学计量比的改变是实现其择优取向转变的主要原因,富O和富Sn薄膜分别利于(001)和(101)结晶取向的实现。而且,我们发现SnO薄膜的拉曼特征峰与结晶取向具有密切关系。110 cm-1处的拉曼峰强随薄膜中(001)取向织构系数的增加而变小,随(101)取向织构系数的增加而变大。这与根据拉曼选择定则预期的Eg模式拉曼峰随薄膜取向的变化关系相一致,从而确定110 cm-1处拉曼峰为Eg模式,为110 cm-1处拉曼峰的指认同时提供了实验和理论两方面的证据。(2)为了提高双极性Sn O薄膜晶体管的性能,必须寻找平衡和优化电子和空穴两种载流子平衡注入和输运的方法。本研究从调控SnO薄膜的化学计量比和载流子注入势垒高度两个方面入手,通过调控快速退火气氛中Ar含量、SnO背沟道表面添加Al2O3覆盖层以及源漏电极和沟道之间引入Al2O3接触势垒层等手段来优化SnO晶体管的双极性性能。结果表明,化学当量的SnO沟道有利于双极性薄膜晶体管场效应迁移率、开关比和对称性的提高。然而,富Sn情况下金属Sn缺陷的存在会使晶体管双极性性能退化,富O情况下部分SnO易被氧化成Sn O2引起晶体管性能转变为高阻或n型。此外,在源漏和沟道之间引入Al2O3接触势垒层可以减少SnO的表面态、增加空穴的注入势垒,从而提高SnO薄膜晶体管对称性和开关比。最优双极性SnO薄膜晶体管的场效应迁移率和开关比在n型工作区分别为2.85 cm2V-1S-1和1.3×103,在p型工作区分别为0.90 cm2V-1S-1和1.7×103。
[Abstract]:Bipolar thin film transistors can realize controlled injection and transport of holes and electrons by changing the polarity and size of gate and source / drain voltages. The complexity of circuit fabrication. In recent decades, thin film transistors with oxide semiconductors as channels have higher field effect mobility, smaller sub-threshold swing, larger switching ratio, better transparency, Many advantages, such as low temperature preparation and compatibility with silicon based process, have attracted much attention. However, most oxide semiconductor thin film transistors exhibit unipolar n or p type, and are related to bipolar oxide semiconductor thin film transistors. The realization of bipolar oxide thin film transistors, Facing the challenges of channel material performance optimization and device structure design, Sno _ 2O _ 3 is used as channel layer material in this paper. The main results are as follows: (1) in this study, the crystal orientation control and Raman characteristic peaks of polycrystalline SnO thin films have been realized. The experimental results show that the change of stoichiometric ratio in Sno films is the main reason for the preferential orientation transition. Moreover, we found that the Raman characteristic peak of SnO thin films is closely related to the crystalline orientation. The Raman peak intensity at 0.110 cm-1 decreases with the increase of the texture coefficient of the SnO films. This is consistent with the expected relationship between the Raman peak of Eg mode and the orientation of the film according to the Raman selection rule, thus determining that the Raman peak at 110 cm-1 is an Eg mode, and that the Raman peak of the film increases with the increase of the orientation coefficient of the film, which is consistent with the expected relationship between the Raman peak and the orientation of the film. In order to improve the performance of bipolar Sno thin film transistors, both experimental and theoretical evidences are provided for the identification of Raman peaks at 110 cm-1. The methods of equilibrium and optimization of electron and hole equilibrium injection and transport must be found. In this study, the stoichiometric ratio and carrier injection barrier height of SnO thin films are regulated. The bipolar performance of SnO transistors is optimized by adjusting the ar content and the addition of Al2O3 overlay on the surface of the back channel in the rapid annealing atmosphere and the introduction of Al2O3 contact barrier layer between the source and leakage electrodes and channels. Chemically equivalent SnO channels can improve the field effect mobility, switching ratio and symmetry of bipolar thin film transistors. However, the existence of Sn defects in Sn rich state will degrade the bipolar properties of the transistors. In the case of rich O, part of SnO is easily oxidized to Sno 2, which causes the transistor performance to change to high resistance or n type. In addition, the introduction of Al2O3 contact barrier layer between source, drain and channel can reduce the surface state of SnO and increase the injection barrier of hole. Therefore, the symmetry and switching ratio of SnO thin film transistors are improved. The optimal field effect mobility and switching ratio of bipolar SnO thin film transistors are 2.85 cm2V-1S-1 and 1.3 脳 103 in n-type workspaces, 0.90 cm2V-1S-1 and 1.7 脳 103 in p-type workspaces, respectively.
【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ134.32;TB383.2

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