磁控溅射法制备AZO透明导电薄膜及其性能的研究

发布时间：2018-01-14 11:03

本文关键词：磁控溅射法制备AZO透明导电薄膜及其性能的研究　出处：《上海工程技术大学》2015年硕士论文　论文类型：学位论文

【摘要】：透明导电氧化物(TCO)薄膜是广泛应用于太阳能电池、平板显示器和传感器等领域的一类薄膜材料,其在可见光波长范围内的平均透过率超过80%,电阻率一般在10-3 Ω·cm以下。锡掺杂氧化铟(ITO)薄膜因为其优异的光电性能是目前应用最为广泛的TCO材料。但是,铟资源的严重短缺造成的高成本以及铟元素具有毒性,使得寻找一种廉价无毒且性能足以媲美ITO的新型透明导电薄膜来替代ITO薄膜势在必行。和传统ITO相比,铝掺杂氧化锌(AZO)薄膜具有资源丰富、廉价无毒、化学和热稳定性能良好等优势,被认为是替代ITO薄膜的最佳候选材料。本文利用射频磁控溅射法(RFMS),在普通载波片上制备了AZO透明导电薄膜。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、原子力显微镜(AFM)、四探针测试仪和紫外-可见分光光度计研究了溅射功率、溅射气压、基底偏压和次级磁场对AZO薄膜表面形貌、粗糙度、晶体结构以及光电性能的影响。实验结果表明：1.制备的AZO薄膜呈六角纤锌矿结构,晶粒沿(002)晶面定向生长。薄膜的晶粒尺寸、表面粗糙度以及(002)面衍射峰强度随着溅射功率的增加逐渐增大。溅射功率较低时,薄膜的生长模式为层状模式,而溅射功率较高时,薄膜的生长模式为岛状模式。薄膜电阻随着溅射功率的增加而减小,溅射功率为150 W时,薄膜的方阻降至30 Ω/□。溅射功率较小时薄膜具有较高的可见光透过率,薄膜的光学带隙宽度随着溅射功率的提高缓慢增加；2.溅射气压较小时,薄膜晶粒尺寸很小,但大小均匀,随着气压的增加,晶粒尺寸逐渐增大,表面粗糙度先增大后减小。溅射气压不超过2.0 Pa时,(002)晶面衍射峰的强度随着溅射气压的增加而增强,说明增大溅射气压可以加快晶粒的生长速度。溅射气压过高会导致薄膜的晶体结构变差,减缓薄膜的生长的速度。溅射气压为0.5 Pa和2.0 Pa时,薄膜具有较高的可见光透过率,其大小受到薄膜厚度、结晶度以及表面形貌等因素的综合影响。溅射气压为2.0 Pa时,AZO薄膜具有最小的方阻,大小为26.59Ω/□,3.施加偏压后,薄膜表面晶粒呈现无定形状(破碎状),但是晶粒大小均匀,结合更为致密,表面无异常大的颗粒形成。晶粒尺寸随基底偏压的升高缓慢增大,表面粗糙度随之增加,薄膜表面呈现更为明显的金字塔结构。溅射偏压没有改变的晶粒生长的择优取向性,但加快了薄膜中其它晶面的生长速度。施加偏压后,薄膜具有很好的可见光透过性,平均透过率超过86%。过高的偏压会起到反溅的作用,对薄膜的生长有不利的影响。4.在传统溅射系统中外加一个次级磁场,引入次级磁场后薄膜的沉积速率从原先的13.04 nm/min提高到了19.93 nm/min:施加次级磁场后薄膜表面平整致密、颗粒大小均匀,结晶质量较高,而不加磁场薄膜表面形貌呈蠕虫状,薄膜质量较差。溅射时间为90 min时,外加磁场前后AZO薄膜方阻分别为30.74Ω/□和12.88Ω/□。次级磁场对薄膜可见光透过率影响不大,但使薄膜的吸收边蓝移现象更明显。运用ANSYS软件对磁控溅射二维磁场分布模拟后发现,次级磁场提高了靶上方横向磁场强度,改善了磁场分布的均匀性,加强了磁场对电子的磁控作用,提高了靶电流,是AZO薄膜的溅射速率、光电性能和形貌结构得到提高和优化的原因。
[Abstract]:Transparent conductive oxide (TCO) thin film is widely used in solar cell, a kind of thin film materials in the field of flat-panel display and sensor, the average in the visible wavelength range through the rate of more than 80%, the resistivity is usually in the 10-3. Cm. Tin doped indium oxide (ITO) thin film because of its excellent photoelectric performance is the most widely used TCO materials. However, a serious shortage of resources caused by the high cost of indium and indium is toxic, and made the new transparent conductive film to find a cheap and non-toxic performance comparable to the ITO to replace the ITO thin film is imperative. Compared with the traditional ITO, Zinc Oxide (AZO) aluminum doped thin films with abundant resources cheap, non-toxic, good chemical and thermal stability and other advantages, is considered to be the best candidate material to replace ITO films. By using RF magnetron sputtering (RFMS), in the common carrier wave plate on the preparation of AZO The transparent conductive film. By using X ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), four probe tester and UV VIS spectrophotometer on the sputtering power, sputtering pressure, substrate bias and secondary magnetic field on the surface morphology of AZO film roughness, crystal structure and the effect of photoelectric properties. The experimental results show that the AZO film 1. prepared at six corners wurtzite structure, grain along the (002) crystal plane orientation growth. The grain size of the films, the surface roughness and the (002) plane diffraction peak intensity gradually increases with the increase of sputtering power. The sputtering power is lower. The film growth mode for layered model, and the sputtering power is high, the film growth mode for the island mode. The thin film resistor decreases with the increase of sputtering power, sputtering power is 150 W, the square resistance film is reduced to 30 / - hour film with the sputtering power was. High visible light transmittance, optical band gap width increases slowly with the increasing of sputtering power; 2. sputtering pressure is lower, the grain size of the films is very small, but the size of uniform, as the pressure increases, the grain size increases, the surface roughness increases first and then decreases. The sputtering pressure (less than 2 Pa. 002) diffraction peak intensity increased with the increase of sputtering pressure, sputtering pressure that can speed up the growth rate of grain. The sputtering pressure is too high will lead to the crystal structure of the films become poor, slow the growth of the film speed. The sputtering pressure of 0.5 Pa and 2 Pa, the film has high visible light transmittance its size is rate, film thickness, surface morphology and crystallinity of the comprehensive influence factors. The sputtering pressure is 2 Pa, AZO thin film has the least resistance, the size is 26.59 ohms per square 3. bias is applied, the surface crystal film The particle shows amorphous shape (broken), but the grain size is uniform, with more compact surface, no abnormal large particle formation. The grain size increases with the substrate bias voltage increases slowly, the surface roughness increases, the film surface is more obvious. The structure of Pyramid preferred orientation growth of grain sputtering without bias change, but to speed up the growth of other planes speed films. Bias is applied after the film has good visible light transmittance and average transmittance of more than 86%. high voltage will play the role of anti splash, the growth of the film has an adverse effect on the traditional.4. sputtering system plus a secondary magnetic field. After the introduction of the secondary magnetic field of thin film deposition rate from 13.04 nm/min increased to 19.93 nm/min: in a secondary magnetic field smooth surface film is dense, uniform particle size, high crystal quality, without magnetic thin film The surface morphology of the wormlike, thin film of poor quality. The sputtering time of 90 min, the magnetic field of AZO films before and after resistance were 30.74 - and 12.88 / Omega / Omega. - secondary magnetic field on film visible light through rate has little effect, but the blue shift of the absorption edge of thin film phenomenon is more obvious. The use of ANSYS software for magnetron the sputtering of two-dimensional magnetic field distribution simulation showed that the secondary magnetic field of the target is increased above the transverse magnetic field strength, improve the uniformity of magnetic field, strengthen the effect of magnetic field on the magnetron electronic, improve the target current, is the sputtering rate of AZO film, the reason to improve and optimize the photoelectric properties and morphology.

【学位授予单位】：上海工程技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.2

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