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用直流溅射法在室温Si基片上制备了 4 .9nm～ 189.0nm范围内不同厚度的Ag薄膜 ,并用X射线衍射及反射式椭偏光谱技术对薄膜的微结构和光学常数进行了测试分析。结构分析表明 :制备的Ag膜均呈多晶状态 ,晶体结构仍为面心立方 ;随膜厚增加薄膜的平均晶粒尺寸由 6 .3nm逐渐增大到 14 .5nm ;薄膜晶格常数均比标准值(0 .4 0 86 2nm)稍小 ,随膜厚增加 ,薄膜晶格常数由 0 .4 0 5 85nm增大到 0 .4 0 779nm。 2 5 0nm～ 830nm光频范围椭偏光谱测量结果表明 :与Johnson的厚Ag膜数据相比 ,我们制备的Ag薄膜光学折射率n总体上均增大 ,消光系数k变化复杂 ;在厚度为 4 .9nm～ 83.7nm范围内 ,实验薄膜的光学常数与Johnson数据差别很大 ,厚度小于 33.3nm的实验薄膜k谱线中出现吸收峰 ,峰位由 4 6 0nm红移至 6 90nm处 ,且其对应的峰宽逐渐宽化 ;当膜厚达到约189nm时 ,实验薄膜与Johnson光学常数数据已基本趋于一致。
Ag thin films with different thickness from 4.9nm to 189.0nm were prepared on Si substrates at room temperature by DC sputtering. The microstructures and optical constants of the films were measured by X-ray diffraction and reflection ellipsometry. The structural analysis shows that the prepared Ag films are polycrystalline and the crystal structure is still face-centered cubic. The average grain size increases from 6.3 nm to 14.5 nm with the increase of film thickness. The average lattice constant The standard value (0.04 0 86 2nm) is slightly smaller. With the increase of the film thickness, the lattice constant of the film increases from 0.0455nm to 0.04779nm. The results of spectroscopic ellipsometry at 250 nm to 830 nm indicate that the optical refractive index n of Ag thin films increases as a whole and the extinction coefficient k changes more complicated than that of Johnson’s thick Ag film. .9nm ~ 83.7nm optical constants of the experimental film and Johnson data vary greatly, the thickness of less than 33.3nm in the experimental film k-line absorption peak, the peak position from 460nm red-shifted to 690nm Department, and its The corresponding peak width gradually widened; when the film thickness reaches about 189nm, the experimental film and the Johnson optical constant data has been basically the same.