【作者】 李爽；

【导师】 张新安；

【作者基本信息】 河南大学 ， 物理电子学， 2018， 硕士

【摘要】 在过去的几十年中,由于金属氧化物薄膜晶体管（TFT）具有优异的电学性质和高的可见光透明度等优点,而被广泛的应用于下一代有源矩阵液晶显示器,有机发光二极管显示器和其他新兴应用电子电路。但是目前,具有高性能的氧化物薄膜晶体管主要由n型材料制备,如ZnO-TFT,SnO₂-TFT、In₂O₃-TFT、InGaO-TFT、IGZO-TFT等。p型氧化物半导体材料的种类较少且难以制备出高质量的薄膜,与n型氧化物TFT相比,对p型氧化物TFT远远落后于n型氧化物TFT,这很大程度上限制互补金属氧化物半导体（CMOS）器件的制备。根据价带化学修饰（CMVB）理论,铜铁矿家族CuMO₂（M=Al,Ga或Cr）材料具有p型电学性质。由于CuAlO₂具有许多特殊的电学,光学,热电和光催化等性能,自1997年首次成功制备以来就受到了广泛关注。尽管CuAlO₂薄膜受到越来越多的关注,但是关于以CuAlO₂薄膜作为沟道的薄膜晶体管的研究却鲜有报道。所以对CuAlO₂-TFT的研究是非常必要的。本文分别使用溶胶凝胶法和磁控溅射法两种方法来制备CuAlO₂薄膜,然后以CuAlO₂薄膜为沟道层来分别制备CuAlO₂-TFT。研究干燥温度、退火温度,不同沟道层厚度等因素对CuAlO₂-TFT电学性质的影响。研究内容主要包括以下三项:（1）使用溶胶凝胶的方法,在SiO₂/Si或石英玻璃衬底上制备CuAlO₂薄膜。通过对薄膜表征发现:本实验制备的CuAlO₂薄膜,在350℃和400℃进行干燥制备的薄膜有利于CuAlO₂的结晶,在氮气气氛条件下经过1000℃退火处理的CuAlO₂薄膜,在可见光范围内具有较高的光学透过率,较宽的禁带宽度（Eg=3.7eV）,较大的晶粒尺寸和平整的表面。（2）利用溶胶凝胶法制备结构为Si/SiO₂/CuAlO₂/Cu的底栅式TFT,研究了干燥温度、退火温度和沟道层厚度对器件各项性能参数的影响。通过电学性能表征,以重复旋涂4层（厚40nm）,在350℃干燥和1000℃退火后的薄膜为器件的沟道层时,得到性能优化的TFT,这些结果表明,TFT性能强烈依赖于CuAlO₂沟道层的结晶性和表面形态。（3）采用磁控溅射法,在SiO₂/Si衬底上制备CuAlO₂薄膜,通过对薄膜的表征,优化薄膜的制备条件,最好的生长参数为:室温、本地真空为5×10^-4Pa;氧氩比为5:50;功率为70W,溅射起压为2Pa。通过表征发现,在此条件下沉积,然后经过不同温度退火的CuAlO₂薄膜,在900℃退火的CuAlO₂具有优化的薄膜性能,即在可见光范围内具有较高的光学透过率,较宽的禁带宽度,较大的晶粒尺寸和平整的表面。并且在优化的实验条件下制备CuAlO₂-TFT;在900℃条件下得到性能较好的CuAlO₂-TFT。更多还原

【Abstract】 In the past few decades,the metal oxide simeconductor thin-film transistors（TFTs）have been extensively investigated for the next generation active matrix liquid crystal displays,organic light emitting diode displays,and other emerging applications electronic circuits due to their excellent electrical properties and outstanding optical transparency.However,most high-performance oxide thin film transistors are made of n-type materials,such as ZnO-TFT,SnO₂-TFT,In₂O₃-TFT,InGaO-TFT,and IGZO-TFT.Due to the lack of p-type oxide semiconductor materials and the difficulty in growing high quality thin films,only little research has been conducted on p-type oxide TFTs,which greatly limits the fabrication of complementary metal oxide semiconductor（CMOS）circuits.Based up the theory of"the chemical modulation of the valence band",it was found that the delafossite CuMO₂（M=Al,Ga or Cr）material has p-type conductivity properties.And CuAlO₂ have attracted a lot of research since 1997contribute to the special properties of electrical,optical,thermoelectric and photocatalytic.Although CuAlO₂ films has received increasing attention,there are only a few reports focusing on p-type TFT using CuAlO₂ films as active layer.Therefore,it is very necessary to study the CuAlO₂-TFT film.In this paper,CuAlO₂ thin films were prepared by sol-gel method and RF magnetron sputtering method respectively.The influence of drying temperature,annealing temperature and thickness on the structural of CuAlO₂ thin films were investigated in detail.（1）The CuAlO₂ thin films were deposited on SiO₂/Si or quartz glass substrates by Sol-gel technique.Through a series of experiments,it was found that CuAlO₂ thin films dried at 350°C and 400°C are conducive to the crystallization of CuAlO₂.And the CuAlO₂ annealed at 1000°C under nitrogen atmosphere has higher visible light transmittance,wider bandgap（Eg=3.7 eV）,larger grain size,and smooth surface.（2）Bottom-gate CuAlO₂ thin film transistor were fabricated by Sol-gel technique.The influence of drying temperature,annealing temperature and thickness on the structural of CuAlO₂ thin films transistors were investigated in detail.These results show that thin-film transistor by using a 40nm thickness,drying at350°C and annealing at 1000°C the CuAlO₂ thin film as active layer has a optimized performance。（3）Finally,the CuAlO₂ thin films were deposited on SiO₂/Si substrates by RF magnetron sputting technique.Through a series of experiments,it was found that the film had high crystal guality and grain fabulous when the temperature was room temperature,the power was 38W,the ratio of O₂:Ar=5:50 and the pressure was 2Pa.These results show that the CuAlO₂ thin film deposited under these conditions has optimized thin film properties,ie,higher visible light transmittance,wider bandgap,larger grain size and flatness.Then CuAlO₂ thin films were deposited on SiO₂/Si substrates by sputting technique using bottom-gate top-contact configuration with bottom gate.These results show that the electrical properties of TFTs are depended on the annealing temperature.With the incresse of the annealing temperature,the performance of the device increase.The TFT fabricated by the CuAlO₂ thin film annealed at 900°C as active layer has a optimized performance。更多还原