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(英文)

Characterization of low-Z material layer profiles in bilayer structures by X-ray reflectivity measurement

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。

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/cm^3 , while the deposition rate of C layer is 0.058 nm/s under our laboratory conditions.