溅射功率对氧化铝薄膜结构和光学性能的影响

采用射频反应磁控溅射法,在K9双面抛光玻璃基底上制备了一系列不同溅射功率的Al2O3薄膜,并对部分薄膜进行退火处理.利用X线衍射法对Al2O3薄膜退火前后的晶体结构进行分析,采用椭圆偏振光谱仪对薄膜的厚度、折射率和消光系数进行测试和拟合.实验结果表明:测射功率在100~300 W时,沉积的Al2O3薄膜退火前后均为非晶态;薄膜在可见光范围内具有良好的透光性能,透射率接近90%,为透明膜;薄膜的沉积速率随溅射功率的增大而增大;薄膜在可见光波段的折射率n随波长的增大而减小,平均值随溅射功率的增大呈现出先增大后减小的变化趋势;薄膜消光系数k的平均值亦随溅射功率的增大呈现先增大后减小的变化趋势.

Effects of sputtering power on structure and optical properties of Al2O3 thin films

Al 2 O 3 thin films were deposited on well-polished K9 glass by radio-frequency reactively magnetron sputtering technique under different sputtering powers,where a pure aluminum target and 99.99% oxygen were employed,and some films were annealed.The structures of both the as-deposited and the annealed films were analyzed by X-ray diffraction（XRD）.The optical properties,such as thickness,refractive index as well as extinction coefficient of the films were measured and simulated by the ellipsometer.The results show that all the films,either as-deposited or annealed,are amor phous,when the sputtering power is 100-300 W.The films are transparent in the visible,presenting transmittance more than 90%.The deposition rate increases with increasing sputtering power.Within the visible range,the refractive index decreases as wavelength becomes larger.As the sputtering power increases,the average refractive index and extinction coefficient of the film increase,but then de-crease while the sputtering power increases further.