欠氧化气氛下等离子体辅助脉冲直流磁控溅射高纯度Al_2O_3薄膜

Growth of High Purity Alumina Coatings by Plasma Assisted Pulse-DC Reactive Magnetron Sputtering under Less Oxidation Condition

为实现高纯度氧化铝薄膜的快速稳定溅射沉积,采用非平衡闭合磁场孪生靶技术,利用脉冲直流磁控溅射方法,首先对溅射电压随氧流量的迟滞现象进行了研究,在此基础上,提出了一种新型的等离子体辅助溅射沉积方法。溅射过程处于迟滞回线的金属模式,保证了高的溅射速率;在真空室内引入一等离子体放电区,沉积在工件上的超薄层非化学计量比氧化铝薄膜,高速通过等离子体放电区时,放电区内解离的氧原子使得氧化铝薄膜被进一步氧化,同时放电区内的氩离子对薄膜进行轰击,增加了薄膜的致密性。利用该方法在不同等离子体功率下进行了氧化铝薄膜的制备,分别利用分光光度计、椭偏仪、原子力显微镜对薄膜的光学特性、表面形貌进行了表征,表征结果说明利用该等离子体辅助磁控溅射方法可获得高纯度的致密氧化铝薄膜。

A novel technique was developed to synthesize highly pure alumina coatings. The original work was the introduction of a plasma discharge reaction field with high ionization rate into the vacuum chamber. Firstly, the thin sub- stoichiometric alumina coatings were deposited in the metal mode of the hysteresis loop of non-balance closed magnetron field twin-target pulse-dc magnetron sputtering, to ensure a high deposition rate. Next, when rapidly passing through the plasma discharge area, the thin sub-stoichiometric almnina coating turned into non-absorbing alumina coating because of a complete oxidation by atomic oxygen, accompanied by an argon ion bombardment, resulting in anincreased compactness of the coatings. The impacts of the synthesis conditions, including the plasma power, deposition rate, and gas flow rate, on the microstructures and optical properties were evaluated. The alumina coatings were characterized with ellipsometry and atom force microscopy. The results show that the newly-developed technique is capable of synthesizing highly pure, compact, dense alumina coating.