I am trying to measure the thickness of a polypropylene thin-film by ellipsometry but I can not find the n&k file to adjust the measurement.
I can not find either the parameters of the dispersion law (Cauchy) I could use to get the thickness of the polymer.
If anyone has any suggestion I will be really grateful.
Thanks a lot
Ana
The refractive index is in eth range 1.47-1.49, the absorption coeffcieitn will be strongly wavelength dependent and can for some selected wavelengths be obtained from the penetration depth radiation for some selected wavelengths, as eg tabulated ithent i ntethenti here: thent
https://application.wiley-vch.de/books/sample/3527409726_c01.pdf
Which ellipsometer do you use? What is the substrate and how does the film grow? If rough and thickness nonuniformity is present, then you will need to take into account, the effect of depolarization. Measurement of raw data is important and if delta is close to 0 or 180, then you need to increase number of measurement points with two or three angles of incidence. You can first select a transparent region and do a normal fit and then model for absorbing part through oscillators. I can look into it if you have a data file generated by a J.A.Wollam ellipsometer.
Hi Ana,
I think you need to get n an k vs wavelength, thus I see if you can measure reflectance and then obtain n as function to the wavelength.
Thanks a lot for your help. The PP sample was on top of an Alumnium substrate and I could finally get the thickness using an interferometer.
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