Al-Zn-Sn-O薄膜晶体管制备与研究

发布时间：2018-04-21 06:39

本文选题：AZTO + 氧化物薄膜　；参考：《吉林建筑大学》2017年硕士论文

【摘要】：近年来,科技水平的不断进步,带动着智能可穿戴电子器件行业蓬勃发展,电子显示器件逐渐受到人们的日益关注。薄膜晶体管作为电子显示屏幕中的核心部件,在屏幕弯曲、可穿戴、携带方便的显示器件中具有广泛应用。氧化物薄膜晶体管由于具有更好的稳定性和更高的迁移率,而且易于在室温下制备,使其在屏幕显示领域上的研究具有重要意义。在氧化物半导体薄膜晶体管中,被广泛研究的是铟镓锌氧(IGZO)薄膜晶体管。In和Ga在自然界中都属于稀有有毒元素,不利于大规模的商业化生产与制备,寻找新型无铟氧化物材料作为薄膜晶体管有源层的研究成为国内外研究的重点之一。研究发现,非晶氧化物薄膜材料(IGZO)具有较高的迁移率,主要原因是薄膜中的金属离子外层电子排布需满足(n-10)d10ns0(n≥4,其中n为主量子数)。同时,为获得稳定的器件性能,薄膜中需要有与氧结合能较高的金属离子,来抑制氧空位的形成。针对以上两点,在AZTO薄膜中,Sn也满足(n-1)d10ns0(n≥4)电子结构,在薄膜内也充当提供载流子浓度的作用,而Al3+和O2-结合能比Ga3+和O2-的结合能高,也可以实现调控载流子浓度的作用,所以理论分析上可以实现替换并制备出高性能的AZTO氧化物薄膜来替代IGZO薄膜。由于Al和Sn在大自然中存储量大且对人体没有危害,通过Sn元素代替In元素,Al元素代替Ga元素,来制备性能优异的薄膜晶体管,对未来可穿戴、便携显示器件的广泛应用具有重要意义。本文以金属Al靶、ZnO和SnO2陶瓷靶作为制备有源层AZTO的材料,利用磁控溅射共溅射的方法,制备新型无铟氧化物AZTO薄膜并研究其薄膜晶体管性能。通过对不同生长条件下制备的AZTO薄膜进行测试分析结果发现:在固定生长气压、生长温度,不同氧分压对AZTO薄膜的影响,氧分压对Al元素的调控具有显著的影响,随着氧分压的增加Al元素锐减,而Al在AZTO薄膜中具有抑制载流子浓度的作用,所以导致薄膜载流子浓度升高。当氧分压为5%时,AZTO薄膜拥有较好性能;EDX检测薄膜内的Al、Sn、Zn原子比近于2:1:1,薄膜霍尔迁移率为3.507cm2V-1s-1,薄膜载流子浓度为2.950E+18。基于此在5%氧分压环境下,分别研究了不同生长温度和生长压强对AZTO薄膜的影响。结果发现温度在80℃时,薄膜霍尔迁移率为2.146+01 cm2V-1s-1,薄膜载流子浓度为4.323E+17,薄膜的性能较好;在生长压强为8 mTorr时,AZTO薄膜生长质量较好,霍尔迁移率3.507 cm2V-1s-1和载流子浓度2.950E+18。最后我们采用lift-off工艺,制备反交叠型结构的AZTO薄膜晶体管。在氧分压为5%,生长压强为8 mTorr,衬底温度为80℃的环境下,利用磁控溅射共溅射金属Al靶、Zn O和SnO2陶瓷靶制备薄膜晶体管的有源层,分别制备了其厚度为20 nm、50 nm、80 nm、120 nm的AZTO薄膜晶体管,并对其电学性能进行了测试分析。结果发现:有源层厚度对器件性能的影响很大,当有源层厚度太薄时,载流子数量太少,迁移率过低;而当有源层厚度过厚时,一方面会增大载流子注入电阻,另一方面厚度过厚将会引起载流子数量过多,发生散射,结果都会使得迁移率有所下降。当薄膜晶体管有源层为50 nm时,薄膜晶体管的迁移率为2.17 cm2V-1s-1,阈值电压14V,开关电流比为1.84×104,器件综合性能相对较好。
[Abstract]:In recent years, the continuous progress of the level of science and technology has led to the rapid development of the intelligent wearable electronic device industry. The electronic display devices have gradually attracted more and more attention. As the core components of the electronic display screen, thin film transistors are widely used in the screen bending, wearable and portable displays. Oxide thin film crystals are widely used. Because of its better stability and higher mobility, and easy to prepare at room temperature, it is of great significance in the field of screen display. In oxide semiconductor thin film transistors, indium gallium zinc oxygen (IGZO) thin film transistors.In and Ga are all rare and toxic elements in nature. A large scale of commercial production and preparation, looking for new indium oxide materials as the active layer of thin film transistors has become one of the focus of research at home and abroad. It is found that amorphous oxide film material (IGZO) has high mobility, the main reason is that the metal ion outer layer in the film needs to meet (N-10) d10ns0 (n). At the same time, in order to obtain the stable n quantum number, in order to obtain the stable device performance, the film needs to have a higher metal ion with oxygen to suppress the formation of oxygen vacancy. In the AZTO film, Sn also satisfies (n-1) d10ns0 (n > 4) electronic structure, in the film also acts as a carrier concentration, while Al3+ and O2- are combined. The combination of Ga3+ and O2- can be higher and can control the carrier concentration, so the theoretical analysis can replace and prepare the high performance AZTO oxide film to replace the IGZO film. Since Al and Sn have large storage and no harm to the human body, the Sn element is replaced by the In element and the Al element is replaced by the Ga element. To prepare thin film transistors with excellent performance, it is of great significance for future wearable and portable display devices to be widely used. In this paper, metal Al targets, ZnO and SnO2 ceramic targets are used as materials to prepare active layer AZTO. A new type of indium oxide AZTO film is prepared by magnetron sputtering co sputtering and the properties of its thin film transistors are studied. The results of the test and analysis of AZTO films prepared under different growth conditions showed that the influence of the fixed growth pressure, the growth temperature and the different oxygen pressure on the AZTO film, the oxygen partial pressure had a significant effect on the regulation of the Al element, and the Al element decreased sharply with the increase of oxygen partial pressure, while Al had the effect of inhibiting the carrier concentration in the AZTO film. So the concentration of the film carrier is increased. When the oxygen partial pressure is 5%, the AZTO film has better performance; the Al, Sn, Zn atom ratio of the thin film is near 2:1:1, the film Holzer mobility is 3.507cm2V-1s-1, the film carrier concentration is 2.950E+18. based on this 5% oxygen partial pressure environment, and the different growth temperature and growth pressure are studied to AZ respectively. The results show that the film Holzer mobility is 2.146+01 cm2V-1s-1, the film carrier concentration is 4.323E+17, and the film has better performance when the temperature is 80 C. The growth quality of AZTO film is better when the growth pressure is 8 mTorr, and the migration rate of the film is 3.507 cm2V-1s-1 and the carrier concentration 2.950E+18., finally, we use lift-off process. AZTO thin film transistors with reverse overlapping structure are prepared. Under the conditions of oxygen partial pressure of 5%, growth pressure of 8 mTorr, and substrate temperature of 80 C, the active layers of thin film transistors are prepared by magnetron sputtering co sputtering metal Al targets, Zn O and SnO2 ceramic targets to prepare the AZTO thin film transistors with thickness of 20 nm, 50 nm, 80 nm, 120 nm respectively. The results show that the active layer thickness has a great influence on the performance of the device. When the thickness of the active layer is too thin, the carrier number is too small and the mobility is too low. While the thickness of the active layer is too thick, the carrier injection resistance will be increased on the one hand. On the other hand, too thick the thickness of the active layer will cause excessive carrier number and scattering, When the active layer of the thin film transistor is 50 nm, the mobility of the thin film transistor is 2.17 cm2V-1s-1, the threshold voltage is 14V, the switching current ratio is 1.84 * 104, and the integrated performance of the device is relatively good.

【学位授予单位】：吉林建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN321.5

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