用X射线反射测量法表征双层结构中低原子序数材料的特性

摘要

A convenient method,low-angle X-ray reflectivity measurement method,is presented to characterize the parameters of low-Z material layers in bilayer structures using X-ray diffractometer (XRD).Because the low-Z material optical constant is similar to the silicon(Si)substrate,the change of the low-Z material layer profiles is difficult to determine.Therefore,an ultra-thin metal layer is deposited as the Base Layer(BL)onto the substrate prior to the low-Z material layer.By choosing chromium(Cr)as the BL material,three Cr/C bilayer films with different C deposition times are fabricated and measured.After the simulation of the reflectivity curves,the density of C is approximately 2.25 g/cm3,while the deposition rate of C layer is 0.058 nm/s under our laboratory conditions.%介绍了用X射线反射测量术表征双层薄膜中低原子序数材料特性的方法.由于低原子序数材料的光学常数与Si基板材料的光学常数非常接近,用X射线反射法确定镀制在Si基板上的低原子序数材料膜层结构的变化十分困难,因此,提出了在镀制低原子序数材料前,首先在基板上镀制一层非常薄的金属层的方法.实验中,选用cr作为金属层材料,制备并测试了三种不同C膜镀制时间的Cr/C双层薄膜.反射率曲线拟合结果表明,C膜密度约为2.25 g/cm3,沉积速率为0.058 nm/s.