Scherrer formula is used for finding the size of nano-scale particles. Can it give a correct estimate of thin film thickness? If so, how accurate it would be?
Hi Fozia Aziz. Usually, as you said, Scherrer formula is used to calculate the particle size. There is another formula to calculate thin film thin film thickness based on reflectivity of X-ray on the surface. You can consult the measurement here:
http://semiconductorslab.com/pdfs/MatSciPoland%20(Determination%20of%20the%20thickness%20and%20optical%20constants%20of%20transparent%20indium-doped%20ZnO%20thin%20films%20by%20the%20envelope%20method).pdf
http://www.rigaku.com/downloads/journal/RJ26-2/RJ26-2_1-9.pdf
Thanx Son Nguyen...I am aware of this method of calculating film thickness via XRR measurement. Actually when I tried doing Reflectivity measurements on my films I did not get any fringe like pattern. Through AFM I have seen that the surface roughness of my films is quite large due to which I can not measure the thickness through reflectivity. Now I require thin film thickness for various calculations but I am not able to do so.. so I was thinking if I could find any alternate method.
What material you have deposited on which substrate, and what is the order of roughness you obtained from AFM measurements. There are several other techniques to measure thickness such as step surface profiling, ellipsometry etc.
Go through the paper hope you will find the solution.
Rev. Sci. Instrum. 65, 2874 (1994); doi: 10.1063/1.1144631
Hi Fozia Aziz, I have the same question with Amol Singh. Could you tell us the materials of your sample and can you roughly guess thickness of your sample? In the case that XRR or AFM can not work with your sample, you can try with SEM or TEM. By observing the cross-section of your film, you can get some information about your film thickness.
I have deposited Fe doped BaTiO3 on SrTiO3(100) substrates. From AFM I found the surface roughness is around 0.8-1 nm (8-10 Angstrom). I made a film with step but the step was not too sharp. I could roughly calculate the thickness to be around 200nm from AFM data. I have also observed small equally spaced globules on the film surface in the AFM images of my films. Could that be another reason for not getting proper reflectivity data??
Dear Fozia roughness is not the reason you have not observed the fringes in reflectivity data. Actually reflectivity technique will not work for high thickness films. In your case thickness is very high 200nm so you will not get any fringe in the data. So you better try some other technique as suggested by Son Nguyen.
Here is a free fitting program that can be used to calculate thickness. I am very new to the field of thin films so I am by no means an expert (Im an undergraduate). But the guy who developed the program is very nice and might be willing to help. This is a fitting program so you can upload your thin film reflectance or ellipsometry data and use the program to fit theoretical data to your measured and this can give you your thickness. I just started using the program.
http://franko.github.io/regress-pro/
Dear Fozia...Hope you have determined the thickness of the thin film by now.. There is another method of determining the thickness of thin films..it is by using Focused Ion Beam technique which generates ion induced secondary electron images...pretty useful instrument for thin films...I am not prying..but you could give it a go if the facilities are available.
Dear all,
I have a question.
If we suppose that the broadening is just because of the limited coherence size and our film is completely single crystal (without any defect), is it possible to determine the thickness through Scherrer Formula?
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