Can it possible to measure oxide thickness in 7 micrometer thin film coating through XRR? Currently XRR system giving alignment error. It may be due to such thin sample (7 micrometer).
Welcome for any suggestion.
Is the film itself or the whole sample 7um?
If it's the whole sample, it might not be microscopically flat enough so that you don't see anything.
If it's the film itself, that's actually pretty much for XRR, especially when it's a heavy metal.
Uday Kumar, For any XRR measurement, the film roughness should be very less (~
Dear Uday Kumar ,
in addition to the answers of Jürgen Weippert and Nitish Kumar ,
I would like to add that the thickness of a 7µm film itself cannot be measured via XRR because your angular resolution will not be fine enough to resolve the peak distances*) of about 0,01mrad (in theta; Cu K-alpha radiation) of the Kiessig fringes.
An oxide layer (of far less than 7µm) on top of the 7µm film can be measured, however film roughness as well as film flatness have to be sufficient, as mentioned above.
*) d ~ lambda/(2*deltatheta); deltatheta = fringe distance in theta
Hi Jürgen Weippert , Thanks for your response. In current situation whole sample is 7um. May you suggest any alternative method to measure oxide thickness.
With best regards
Dear Nitish Kumar , Thanks for your response. It has helped to understand the importance of roughness value for XRR. May you suggest any alternative method to measure oxide thickness.
With best regards
Dear Gerhard Martens ,
I am very thankful for your detailed explanation. May you suggest any alternative method to measure oxide thickness (5 to 100nm thick).
With best regards
The difficulty is that other non-destructive thickness measurements such as ellipsometry are also correlated to the roughness. If your sample is too rough for XRR, ellipsometry will probably be not that great, either.
If you have access to a TEM, you could use that, but most TEMs are so booked that daily routine measurements are not an option. You could cleave the sample and put it in a SEM, but of course that is destructive and gets very unprecise on the thin end of your film thickness range.
If your sample is conducting, you might consider contactless conductivity measurements an option, but of course you would need some calibration points for that.
I would suggest photoelectron spectroscopy, xps, which is well suited to measure oxide thin films on top of the same element. Check e.g. papers from Hans-Henning Strehblow and coworkers, which you will find on RG. Good luck, Dirk
If you can sacrifice a piece of the sample, then I think the easiest approach is to break it and image the cross section in SEM.
TEM would also work but the sample prep is far more complicated and for thickness measurement it's really an overkill.
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