【作者】 祁俊路；

【导师】 李合琴；

【作者基本信息】 合肥工业大学 ， 材料学， 2006， 硕士

【摘要】 氧化铝（Al₂O₃）薄膜具有许多优良的物理化学性能,在机械、光学及微电子等高科技领域有着广泛应用,一直受人们高度关注。尤其是Al₂O₃薄膜具有非常高的硬度（可达20～30GPa）和高温稳定性（α—Al₂O₃熔点为2015℃）,在机械领域作为保护涂层涂覆在器件上可提高寿命减少经济损失。目前,制备薄膜的方法很多,磁控溅射法具有高速、低温的优点得到越来越多的应用。然而溅射工艺参数的选取以及沉积的薄膜结构和性能是人们主要关注的课题。 本文采用射频反应磁控溅射技术在Si（001）和不锈钢衬底上制备出Al₂O₃薄膜,用XRD、AFM、XPS、和显微硬度计等测试手段对沉积的薄膜进行了表征。结果表明,Al₂O₃薄膜沉积速率对射频功率、溅射气压、靶基距、氧气流量等溅射工艺参数有很大的依赖性并随之规律性变化;室温沉积的Al₂O₃薄膜是典型的非晶态结构;薄膜中O:Al位于1.50附近,基本达到理想配比。随着沉积温度的不断增加,Al₂O₃薄膜沉积速率无明显变化;薄膜结构在沉积温度为500℃时开始向晶态γ-Al₂O₃转化;Al₂O₃薄膜的粗糙度R_RMS和Ra都不断增加;薄膜的显微硬度也不断增加。 另外,对沉积在不锈钢衬底上不同厚度的Al₂O₃薄膜进行了800℃/6h和1000℃/6h的退火处理,研究了膜层厚度和退火温度对Al₂O₃薄膜的晶体结构、表面形貌和显微硬度的影响。研究结果表明,膜层厚度对Al₂O₃薄膜的结构基本没有影响,但随厚度的增加,薄膜的显微测试硬度受衬底的影响减小。非晶Al₂O₃薄膜经不同温度退火处理后XRD实验数据表明其相变过程是:非晶a-Al₂O₃→γ-Al₂O₃（主晶相）+α-Al₂O₃+κ-Al₂O₃（800℃）→α-Al₂O₃（主晶相）+γ-Al₂O₃+δ-Al₂O₃+θ-Al₂O₃+κ-Al₂O₃（1000℃）,并且结晶状况愈来愈好,薄膜变得更加致密。薄膜的粗糙度随退火温度的增加而增加,显微硬度也随之不断增大。退火温度为1000℃时,1000nm厚的Al₂O₃薄膜的显微硬度可达23GPa。更多还原

【Abstract】 Aluminum oxide（ Al₂O₃）thin films are widely used in mechanical, optical and microelectronic applications because of their excellent physical and chemical properties. Especially, Al2O3 thin films have very high hardness（up to 20³0 GPa） and very good thermal stability（melting point of α-Al2O3 is 2015℃）. As a result, Al2O3 thin films may be coated on the devices as a protective coating to elongate their lifetimes and decrease the economic loss. At the present time, there are a lot of methods to prepare thin films and magnetron sputtering technique is more and more widely used to deposit all sorts of thin films due to its high sputtering velocity and low temperature. However, it is still a question how to determine sputtering process parameters, microstructure and properties of thin films.In this paper, Al2O3 thin films are successfully deposited by radio frequency （RF） reactive magnetron sputtering on silicon wafer and stainless-steel substrates. The properties of thin films are characterized in terms of x-ray diffraction （XRD）, atomic force microscopy （AFM）, X-ray photoelectron spectroscopy （XPS）, and micro-hardness tester and so on. The result shows that the deposition rates of Al2O3 thin films are dependent on the process parameters used such as radio frequency power, sputtering pressure, target-to-substrate distance, and oxygen flow rate;Al2O3 thin films deposited on room temperature are a typical amorphous and columnar structure;the oxygen/aluminum atomic ratio in the deposited film is in the vicinity of 1.50. With the increase of the substrate temperature, the deposition rate of Al2O3 thin films are very stable, the phase of thin films begins to transit from amorphous Al2O3 to γ-Al2O3 at deposition temperature of 500℃ , the roughness Rrms and Ra and micro-hardness of Al2O3 thin films increase continually.In addition, the different thickness aluminum oxide thin films deposited on stainless-steel substrates are annealed at 800 ℃ and 1000℃ for 6 hours, respectively. It is studied that the film thickness and annealing temperature have an influence on crystalline structure, surface morphology and micro-hardness of Al2O3 thin films annealed. The experimental results show that the film thickness has nearly influence on microstructure, while influence from the substrate on thefilm micro-hardness measured decreases with the increase of the film thickness. XRD shows that the process of phase transition of amorphous aluminum oxide thin film is a-Al2O3-> y-Al2O3 （majority） + a-Al2O3 （minority） +k-A12O3（800°C） ^a-Al2O3（majority）+y-Al2O3 （minority） + 5-Al2O3 + 0-Al2O3 +k-A12O3 （1000°C）. Crystallization and density of films get better. The square roughness and micro-hardness of A12O3 thin films are increasing with the increase of annealing temperature. When the annealing temperature is 1000°C, micro-hardness of A12O3 thin film whose thickness is lOOOnm is up to 23GPa.更多还原