不同氧分压下直流反应溅射ZnO薄膜的结构和光学特性

Structure and Optical properties of ZnO Films DC Reactively Sputtered at Different Oxygen Partial Pressure

在室温,不同氧分压条件下,采用Zn靶直流反应溅射在石英衬底上制备了具有纤锌矿结构(002)择优取向的ZnO薄膜。薄膜的生长速率随氧分压的增大而减小,在20%-30%之间存在一个拐点,在此点之前,溅射产额减小的速率很快,而在此点之后,溅射产额减小的速率减慢了很多,当氧分压在30%以上时,溅射过程中Zn的氧化在靶表面就已经完成。通过单振子模型分析了薄膜的光学特性,采用X射线衍射的方法对薄膜的晶粒尺寸和应力进行分析。研究结果表明在氧分压20%以上时,薄膜在可见光波段具有较好的光学透明性和很高的电阻率。薄膜的光学折射率、晶面间距和内部应力均随着氧分压的增大而增大。并从薄膜生长机理上给出了理论解释。

Thin wurtzite （002） textured ZnO films were deposited on the quartz substrate by DC reactive sputtering with a Zn target at room temperature under different oxygen ratios. The deposition rate of the film will get slow as the oxygen ratio becomes greater. There is a turning point of the oxygen partial pressure between 20 % and 30 %. On the left side of the point, the deposition rate goes slower, meanwhile, the decrease of deposition rate gets even on the right side. When the oxygen ratio gets more than 30 %, the oxidation of Zn is completed on the target surface. The optical properties are investigated with single oscillator model, and the grain size and stress are analyzed with X- ray diffraction. It is proved that ZnO films with good transparence and high electrical resistivity could be obtained while the oxygen ratio is more than 20 %. The refractive index, spacing and stress of ZnO film will increase as the oxygen ratio increases, which is theoretically explained with the method of film growing.