辅助离子束对中频孪生磁控反应溅射制备氧化钛光学薄膜的影响

Influence of Ion-Beam Assistance on Properties of TiO_2 Films Deposited by MF Twin Magnetron Reactive Sputtering

本文利用孪生靶50 kHz中频磁控反应溅射的方法,在多孔阳极层离子束源产生的低温离子束辅助条件下制备了光学性能良好的氧化钛薄膜。利用原子力显微镜、分光光度计、椭圆偏振光谱仪研究了离子束功率以及退火温度对氧化钛薄膜形貌、光学折射率和消光系数、孔隙率等的影响。结果表明:利用中频孪生磁控溅射的方法将沉积工艺控制在反应过渡区,可以有效的抑制钛靶中毒和阳极消失,反应溅射过程稳定;辅助离子束提高了等离子体的电荷密度;氧化钛薄膜堆积密度和光学折射率也有所提高,薄膜表面趋于平坦,孔隙率降低。氧化钛薄膜在高温退火处理时由于出现从非晶到多晶转变以及晶体长大与转变,结构逐渐趋于完整,表面粗糙度不断增加;800℃时完全转化为金红石相,晶粒直径约70 nm。

The TiO2 optical films were deposited by mid frequency twin magnetron reactive sputtering with assistance of anode layer multi-cell ion source on quartz substrates. The film was characterized with atomic force microscopy, ellipsometry and spectroscopy. The influence of the deposition conditions, such as the ion beam assistance, ion power, and annealing temperature, on the microstructures and properties of the film was studied. The results show that the deposition conditions strongly affect the film growth. For instance, deposition at the reactive transition region is fairly stable, and significantly eliminates poisoning and deactivation of the Ti target. The ion-beam assistance improves the surface flatness, compactness and refractive index of the TiO2 films, reducing the pore density possibly because it enhances the charge density in plasma region. The annealing turns amorphous TiO2 into polycrystalline, coinciding with growth of grains. At 800%, rutile phase dominates, with an average grain size of about 70 nm.