【作者】 辛艳青；

【导师】 杨田林；

【作者基本信息】 山东大学 ， 微电子学与固体电子学， 2010， 硕士

【摘要】 随着光电产业的快速发展,各种光电材料不断被开发,透明导电薄膜是其中之一。由于在可见光区域内的高透过率和高导电性,透明导电薄膜被广泛应用。目前,应用较为广泛且制备技术比较成熟的是氧化铟掺锡(ITO)薄膜和氧化锡掺氟(FTO)薄膜,其中ITO应用最为广泛。但是,ITO薄膜价格高、且高温时铟易扩散而出现薄膜性能退化现象。相比而言,氧化锌(ZnO)具有成本低、资源丰富、无毒、稳定性强的优点,因此受到广泛的关注。本文采用射频磁控溅射法,首次在室温下以玻璃为衬底制备出钇掺杂的氧化锌透明导电薄膜(YZO)。系统地研究了制备参数(溅射气压、溅射功率)和薄膜厚度对YZO薄膜的结构和光电特性的影响；利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、霍尔测试仪以及紫外-可见光分光光度计对YZO薄膜的结构、表面形貌、光学和电学性质进行了测量。1、厚度对薄膜性质的影响当溅射气压为2.0 Pa,功率为100 W时,分别制备了厚度为200 nm,400 nm,500 nm,600 nm,800 nm的五个样品,它们的生长速率约为52 nm/min,基本不随时间变化。随着薄膜厚度的增加,YZO薄膜的结晶变好,ZnO(002)峰强度增强,薄膜晶粒尺寸从30.4nm增加到了34.6 nm,晶粒较大,但是晶粒随薄膜厚度变化不明显；由于载流子浓度变化不大,随着结晶变好,晶界散射减小,霍尔迁移率增大,电阻率持续下降,可获得的最低电阻率为8.36×10-4Ω·cm,此时迁移率为15.3 cm2V-1s-1,载流子浓度为4.88×1020cm-3。在波长为500 nm-800nm的可见光范围内,所有样品的平均透过率均在90%以上。2、溅射气压对薄膜性质的影响薄膜厚度均为600 nm,溅射功率为100 W,溅射气压分别为：0.8 Pa,1.0 Pa,1.6 Pa,2.0 Pa,3.0 Pa。随着溅射气压的提高,薄膜生长速率呈下降趋势,当0.8 Pa时的56 nm/min降至3.0 Pa时43 nm/min,晶粒尺寸由47.4 nm减小到31.5nm,薄膜的结晶质量变差。在1.0 Pa时,溅射速率快,薄膜中氧空位多,载流子浓度高可达5.2×1020 cm-3,由于电离杂质散射的影响,霍耳迁移率降低为10.8cm2V-1s-1。溅射气压为2.0 Pa时,可获得最低的电阻率8.9×10-4Q·cm,此时载流子浓度降至4.92×1020 cm-3,霍尔迁移率变为14.2 cm2V-1s-1。随着溅射气压的增加,薄膜的透过率有所降低,但是所有样品在可见光区域内的平均透过率均超过了89%。3、溅射功率对YZO薄膜性质的影响薄膜厚度为600 nm,溅射气压2.0 Pa,衬底不加热,溅射功率分别为：40 W,50 W,60 W,90 W,110 W。随着溅射功率由40 W增加到110 W,溅射速率明显增大,从15 nm/min增加到56 nm/min。总体来看,晶粒尺寸变化不大,基本在33 nm-38 nm之间。当溅射功率为90 W时,载流子浓度达到最大为4.99×1020cm-3,霍耳迁移率只有14 cm2V-1s-1。最佳功率为50 W,其电阻率为8.71×10-4Ω·cm,载流子浓度为4.25×1020 cm-3,霍尔迁移率为16.8 cm2V-1s-1。随着溅射功率的增加,高能粒子对薄膜造成损伤,结晶质量变差,导致光子的散射和吸收增加,薄膜在可见光波段的平均透过率降低,但是平均透过率均在90%以上,说明YZO具有良好的透光性。从带隙来看,随着溅射功率的增加,带隙呈增大趋势,从40 W时的3.54 eV增大到了11OW时的3.64 eV。更多还原

【Abstract】 As the optoelectronics industry develops fast, various optoelectronic materials have been found. Because of its good conductivity and high transparency in the visible light range, the transparent conducting films have been widely used. At present, Indium-Tin Oxide (ITO) film manufactured by mature technologies is the most widely used. However, ITO is expensive, and the Indium can diffuses easily under high temperature, so ITO performance deteriorates. Compared with ITO, zinc oxide has been gained much attention due to its unique advantages, such as low costs, rich resources, non-poisonous, high thermal and chemical stabilities in the field of transparent conducting films.In this dissertation, YZO film has been prepared on the glass substrate by RF magnetron sputtering for the first time. The influence of deposition parameters (sputtering pressure, RF power) and film thickness on the structure, optical, and electrical properties of the YZO film was studied systematically. The structure, surface morphology, and electrical and the optical properties of YZO film have been measured with XRD, SEM, Hall Effect, and UV-Vis Spectrophotometer.1. The influence of film thickness on the properties of the filmFive samples have been prepared with a pressure of 2.0 Pa, power of 100W and unheated substrate. Theirs thickness is 200 nm,400 nm,600 nm, and 800 nm. The growth rate of these five samples is about 52 nm/min, and it will not change as time goes on. As the thickness of the film increases, the crystallization becomes better and the intensity of the (002) peak rises, so the size of the grain has increased from 30.4 nm to 34.6 nm. The grain size is bigger than other grain size of transparent conducting films, but its increasing is unobvious. For the YZO films, with the crystallization of films changing better, Hall mobility increases, the resistivity continue to decline, and the minimum resistivity of 8.36×10-4Ω·cm is available, with a Hall mobility of 15.3 cm2V-1s-1and a carrier concentration of 4.88×1020 cm-3. As the thickness of the film increases, the average transparency of the film decreases, but the average transparency of all the samples is above 90% in the wavelength range of 500 nm to 800 nm.2. The influence of the sputtering pressure on the properties of the YZO filmUnder the condition, the thickness of all films is 600 nm, the sputtering power is 100W, and the substrate is unheated. When the sputtering pressure is 0.8 Pa,1.0 Pa, 1.6 Pa,2.0 Pa and 3.0 Pa, respectively, and YZO films have been prepared. As the sputtering pressure increases from 0.8Pa to 3.0 Pa, the growth rate of the film decreases from 56 nm/min to 43 nm/min yet the size of the grains decreases from 47.4 nm to 31.5 nm, which shows that the crystal quality of the films has deteriorated. When the pressure is 1.0 Pa, the growth rate of the films is faster, more oxygen vacancies exist in the films, and the carrier concentration is 5.2×1020 cm-3., Hall mobility decreases due to ionized impurity scattering, it is 10.8 cm2V-1s-1. When the sputtering pressure is 2.0 Pa, the films with resistivity of 8.9×10-4Ω·cm, a carrier concentration of 4.92×1020 cm-3 and a Hall mobility of 14.2 cm2V"1s"1, has been obtained. With the sputtering pressure increasing, the transmittance of the films decreases. But the average transmittance of all films exceeds 89% in the visible range.3. The influence of the sputtering power on the properties of the YZO filmThe average thickness of the films is about 600 nm, the sputtering pressure is 2.0 Pa, the substrate is unheated, and the sputtering power is 40 W,50 W,60 W,90 W and 110W, respectively. As the sputtering power increasing from 40 W to 110 W, the growth rate increases from 15 nm/min to 56 nm/min obviously, but the grain size changes little between 33 nm and 38 nm. When the sputtering power is 90W, the maximum carrier concentration is 4.99×1020 cm-3, with a Hall mobility of 14 cm2V-1s-1. The optimum power is 50 W, and the resistivity of 8.71×10"4Ω·cm is available with a carrier concentration of 4.25×1020 cm-3 and a Hall mobility of 16.8 cm2V-1s-1. With sputtering power increasing, the crystal quality degenerates. That causes increasing of light scattered by the surface and the photon absorbtion so that the average transparency decreases. The point of view from band gap, as the sputtering power increases, band gap tends to rise. The band gap increases from 3.54 eV to 3.64 eV when the sputtering power increases from 40 W to 110 W.更多还原