2-STEP REGRESSION PROCEDURE FOR THE OPTICAL CHARACTERIZATION OF THIN-FILMS

被引:12
作者
BABU, SV [1 ]
DAVID, M [1 ]
PATEL, RC [1 ]
机构
[1] CLARKSON UNIV,DEPT CHEM,POTSDAM,NY 13676
来源
APPLIED OPTICS | 1991年 / 30卷 / 07期
关键词
DIODE ARRAY REFLECTOMETRY; REGRESSION IN REFLECTOMETRY; 2-STEP REGRESSION; ENVELOPE METHOD; OPTICAL CHARACTERIZATION; OPTICAL PARAMETERS; REFRACTIVE INDEX; ABSORPTION COEFFICIENT; BANDGAP;
D O I
10.1364/AO.30.000839
中图分类号
O43 [光学];
学科分类号
070207 ; 0803 ;
摘要
A diode array rapid scan spectrometer is used for measuring the intensity of polychromatic light in the 300-420-nm range reflected from a diamondlike carbon film as a function of wavelength. With a fixed grating setting, the wavelength range of 120 nm can be covered in 23 ms. From the reflected intensity, a new two-step regression procedure is utilized to determine refractive index, bandgap, slope of the absorption edge, and film thickness. The calculated parameters are independent of the starting set and the sequence of parameter estimation. The accuracy of the regression procedure is verified by comparison to the envelope method. It is shown using simulated data that, for strongly absorbing films, the new regression procedure is more accurate than the envelope method. The new regression method can handle very noisy reflectance spectra also.
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页码:839 / 846
页数:8
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