湿法制备的晶态金属氧化物薄膜及其晶体管性质研究

发布时间：2018-02-24 20:36

本文关键词： 湿法制备晶态薄膜氧化锌锡氧化锡薄膜晶体管(TFT)　出处：《清华大学》2016年博士论文　论文类型：学位论文

【摘要】：湿法制备金属氧化物薄膜及晶体管器件具有工艺简单、化学组分易于调控、成本低、适应大规模生产等优点,在平板显示有源驱动电路中有广阔的应用前景。近年来,湿法制备的氧化物薄膜晶体管(TFT)器件性能已有很大提高,然而大多数高质量氧化物半导体材料组成元素中含有稀缺、昂贵的铟,而且当前报道的许多高迁移率氧化物TFT器件工作模式为耗尽型,无法应用于有源驱动。本论文围绕非铟体系的晶态金属氧化物半导体薄膜的湿法制备,深入研究了物相转变过程、氧化物薄膜微观结构、绝缘层/半导体层表界面性质,开发了新型前驱体溶液体系并优化了制备工艺,获得了高性能氧化锌锡和氧化锡TFT器件。主要成果如下:1.首次报道了前驱体溶液中水分添加对多晶氧化锌锡薄膜结构及TFT器件性能的影响。选用二水合醋酸锌和氯化亚锡为前驱体材料制备氧化锌锡薄膜,发现分段式升温热处理可以诱导薄膜结晶,向前驱体溶液中添加适量水分能促进三元尖晶石型Zn2SnO4晶相的形成及晶粒生长,得到致密的晶态氧化锌锡薄膜。制备了基于原子层沉积氧化铝绝缘层的顶栅底接触TFT器件,发现向前驱体溶液中添加1.67 M水后,器件中载流子迁移率从0.92 cm2V-1s-1提高到2.11 cm2V-1s-1,提升了130%。进一步向前驱体溶液中掺杂5%钇或镧后,器件在正向偏压应力测试1小时后阈值电压漂移由1.05 V分别下降到0.33 V和0.17 V。2.使用湿法加工的氧化铝绝缘层,制备得到高性能氧化锌锡TFT器件。基于氧化锌锡前驱体中水分添加和分段式升温热处理的协同作用,在Al2O3绝缘层上制备了表面形貌平整、结构致密、传输通道畅通、氧缺陷含量较少的多晶氧化锌锡薄膜。当前驱体溶液中Zn/Sn摩尔比例为1:1时,底栅顶接触TFT器件的平均载流子迁移率达到了52.5 cm2 V-1 s-1,开关电流比为2.1×105,阈值电压为2.3 V。3.首次报道使用2-乙基己酸亚锡作为氧化锡TFT器件半导体层前驱体材料,制备得到高性能氧化锡TFT器件。系统研究了热处理温度、前驱体浓度等条件对薄膜结构的影响,优化后获得了结构致密、缺陷含量极少的多晶氧化锡薄膜。采用湿法制备的氧化铝绝缘层,得到了高性能、增强型工作模式的氧化锡TFT器件,并成功实现了对单个有机发光二极管的亮度调控。氧化锡TFT器件的平均载流子迁移率达到96.4 cm2 V-1 s-1,开关电流比为2.2×106,阈值电压为1.7 V。该迁移率是目前报道的湿法制备的氧化锡TFT器件中的最高值。
[Abstract]:The fabrication of metal oxide thin films and transistors by wet method has the advantages of simple process, easy control of chemical components, low cost and suitable for large-scale production. It has a broad application prospect in flat panel display active drive circuits. The properties of oxide thin film transistor (TFT) devices fabricated by wet process have been greatly improved. However, most elements of high quality oxide semiconductor materials contain rare and expensive indium. Moreover, many of the reported high mobility oxide TFT devices are depleted and cannot be used for active drive. This thesis focuses on the wet fabrication of crystalline metal-oxide semiconductor films in non-indium systems. The process of phase transition, the microstructure of oxide film, the interface properties of insulator / semiconductor layer were studied, a new precursor solution system was developed and the preparation process was optimized. High performance ZnO and tin oxide TFT devices have been obtained. The main results are as follows: 1. For the first time, the effects of water addition in precursor solution on the structure of polycrystalline zinc tin oxide films and the properties of TFT devices are reported. Zinc tin oxide thin films were prepared by using stannous chloride as precursor material. It is found that segmental heating treatment can induce the crystallization of the film, and adding proper moisture to the precursor solution can promote the formation of ternary spinel Zn2SnO4 crystal phase and grain growth. Dense ZnO thin films were obtained. A top-gate bottom contact TFT device based on atomic layer deposited alumina insulator was fabricated. It was found that 1.67m water was added to the precursor solution. The carrier mobility in the device increased from 0.92 cm2V-1s-1 to 2.11 cm2V-1s-1.The carrier mobility increased by 130. Further doping of 5% yttrium or lanthanum into the precursor solution, The threshold voltage drift of the device decreased from 1.05 V to 0.33 V and 0.17 V. 2 after 1 hour of forward bias stress test. High performance ZnO TFT devices were fabricated. Based on the synergistic effect of water addition in ZnO precursor and segmental heating treatment, the surface morphology of Al2O3 was smooth, the structure was compact, and the transmission channel was smooth. Polycrystalline zinc tin oxide thin films with less oxygen defect. When the molar ratio of Zn/Sn in precursor solution is 1: 1, The average carrier mobility of bottom gate top contact TFT device is 52.5 cm2 V-1 s-1, the switching current ratio is 2.1 脳 10 5, and the threshold voltage is 2.3 V. 3. It is reported for the first time that stannous 2-ethylcaproate is used as semiconductor layer precursor material for TFT devices. High performance tin oxide TFT devices were fabricated. The effects of heat treatment temperature and precursor concentration on the structure of the films were systematically studied. Polycrystalline tin oxide thin films with very little defect content. High performance and enhanced tin oxide TFT devices were obtained by wet preparation of alumina insulating layer. The average carrier mobility of tin oxide TFT device is 96.4 cm2 V-1 s-1, the switching current ratio is 2.2 脳 10 6, and the threshold voltage is 1.7 V. this mobility is reported by wet method. The maximum value in the available tin oxide TFT device.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN321.5;TB383.2

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