阳极氧化法制备TFT绝缘层研究

发布时间：2018-01-21 16:53

  本文关键词： 阳极氧化 电子束蒸发 绝缘层 Mg-Al合金薄膜　出处：《深圳大学》2017年硕士论文　论文类型：学位论文

【摘要】：显示屏是人机交互的界面,越来越成为人们工作生活中不可或缺的角色。非晶氧化物半导体薄膜晶体管(AOS-TFT)具有载流子迁移率高(1~100 cm2V-1s-1)、薄膜均匀性好、工艺温度相对较低、薄膜对可见光透明、与现有a-Si TFT制备工艺兼容等优点,是下一代显示技术的有力竞争者。但AOS-TFT难免使用高真空、高能量等昂贵真空设备进行氧化物薄膜蒸镀,一方面使得氧化物薄膜的氧空位难以控制,另一方面不利于TFT的低温制备,无法满足电子纸、透明显示等新型显示器件的发展需求。阳极氧化法设备简单,成本低廉,能实现TFT的低温制备,本文首次探索阳极氧化Mg-Al合金实现复合氧化物薄膜的制备,并对其结构、绝缘性能等进行了研究,主要工作和研究结果如下:1.对比电子束蒸发和磁控溅射蒸镀方式,发现单源电子束蒸发和磁控溅射难以控制薄膜的Mg、Al比例,采用Mg、Al金属两种靶材,通过双源电子束蒸发可以很好控制薄膜的成分比例。2.经合金薄膜的EDS、SEM等表征,其结果表明,在优化电子束蒸发的束流大小、靶材、基板温度的工艺参数下,通过调整束流能够得到期望比例的Mg-Al合金薄膜,合适的束流和高纯Mg粒、Al粒靶材以及180℃的基板温度,可以提高薄膜的质量,得到表面形貌平整、致密的合金薄膜。3.在阳极氧化方面,首先通过铝膜的阳极氧化制备氧化铝簿膜,并获得了性能较好的氧化铝绝缘层,以此验证金属阳极氧化制备氧化物薄膜的可行性。在此基础上,进行了通过阳极氧化Mg-Al合金薄膜制备Mg-Al复合氧化物薄膜的研究。研究表明,阳极氧化中恒定电流大小、恒定电压大小、恒压时长以及Mg-Al合金薄膜成分比例均对氧化膜的绝缘性能有影响。采用合适比例的Mg-Al合金薄膜和2mA-85V、3mA-85V的恒流恒压参数可以得到质量较高的氧化物薄膜,适当延长恒压氧化的时间可进一步减少薄膜的缺陷,降低薄膜的漏电流。4.薄膜经过退火处理,可以降低薄膜的粗糙度和缺陷,进一步降低漏电流。综合优化工艺参数,阳极氧化薄膜的漏电流为10-4mA/cm2量级,击穿电压约为20V,相对介电常数8.35,将氧化膜作为TFT的绝缘层,器件表现出一定的场控效应。
[Abstract]:The display screen is the interface of human-computer interaction. Amorphous oxide semiconductor thin film transistors (AOS-TFTs) have a high carrier mobility of 100 cm2V-1s-1). The film has the advantages of good uniformity, relatively low process temperature, transparent to visible light and compatible with the existing a-Si TFT fabrication process. However, AOS-TFT inevitably uses high vacuum, high energy and other expensive vacuum equipment for oxide film evaporation. On the one hand, the oxygen vacancy of oxide film is difficult to control. On the other hand, it is not conducive to the preparation of TFT at low temperature and can not meet the development needs of new display devices such as electronic paper, transparent display, etc. The anodizing process is simple in equipment and low in cost, and can realize the low temperature preparation of TFT. In this paper, the preparation of composite oxide films by anodic oxidation of Mg-Al alloy was investigated for the first time, and its structure and insulation properties were studied. The main work and results are as follows: 1. Compared with the methods of electron beam evaporation and magnetron sputtering evaporation, it is found that the ratio of mg / Al in single source electron beam evaporation and magnetron sputtering is difficult to control. The composition ratio of Al metal target can be well controlled by double source electron beam evaporation. The results show that the composition ratio of Al metal target can be well controlled by EDS- SEM of the alloy film. The desired ratio of Mg-Al alloy film, appropriate beam current and high purity mg particles can be obtained by adjusting the beam current under the optimized parameters of beam size, target material and substrate temperature of electron beam evaporation. Al particle target and substrate temperature of 180 鈩，

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