椭偏与光度法联用精确测定吸收薄膜的光学常数与厚度  

Accurate determination of optical constants and thickness of absorbing thin films by a combined ellipsometry and spectrophotometry approach

作　　者：周毅[1] 吴国松[1] 代伟[1] 李洪波[1] 汪爱英[1] 

机构地区：[1]中国科学院宁波材料技术与工程研究所,宁波315201

出　　处：《物理学报》2010年第4期2356-2363,共8页Acta Physica Sinica

基　　金：宁波市自然科学基金(批准号:2008A610054)资助的课题~~

摘　　要：介绍了一种同时利用椭偏仪和分光光度计精确测量薄膜光学常数的方法,并详细比较了该方法与使用单一椭偏仪拟合结果的可靠性.采用可变入射角光谱型椭偏仪(VASE)表征了250—1700nm波段辉光放电法沉积的类金刚石薄膜,研究发现当仅用椭偏参数拟合时,由于厚度与折射率、消光系数的强烈相关性,无法得到吸收薄膜光学常数的准确解.如果加入分光光度计测得的透射率同时拟合,得到的结果具有很好的惟一性.该方法无需设定色散模型即可快速拟合出理想的结果,特别适合于确定透明衬底上较薄吸收膜的光学常数.A new approach for accurate measurement of the absorbing film thickness and optical constants by combined ellipsometry and spectrophotometry is introduced.The details are studied in terms of the mathematical models and formulats in comparison with the commonly used method which is only dependent on the ellipsometry data specifically.Using variable angle spectroscopic ellipsometry（VASE）,the diamond-like carbon film deposited by a glow discharge technique was characterized at the wavelength range of 250—1700 nm.The results indicate that,generally,it is rather difficult to determine the thickness and optical constants of absorbing film accurately and rapidly due to the strong correlation between thickness and n,k.By simultaneously fitting ellipsometry parameters and film transmittance,however,the optical constants could be obtained easily and accurately from a unique solution without any predetermined dispersion model.The fitting results of DLC show that this approach is a promising method to determine the thicknesses and optical constants of films,especially of the thin absorbing films.

关 键 词：光学常数 光谱型椭偏仪 吸收薄膜 透射率 

分 类 号：O484.41[理学—固体物理]