I have grown ultra-thin ~2 nm ZnO thin films thorugh the deposition techinque ALD.
And now I want to confirm the value of the thickness through Ellipsometry with a HORIBA iHR 320 Ellypsometer.
What can be the best optical model to use in this case?
I have looked up the Cauchy Model which I think it is one of the simplest models to use... but, will it give the best results?
I also looked up to a other known model called as a: New Amorphous Model. reported by Jeong-Eun Kim, Seung-Muk Bae, Heesun Yang, and Jin-Ha Hwang (2010)
Can someone give me more help ..?
Thank you ! :)
At this scale of thickness, ellipsometric analysis is challenging. Be sure to know perfectly substrate before start. Cauchy might do the job as there are few chances to be sensitive to k at such small scale and if your instrument doesn't go below 300nm. Be ready to do statisctics on several similar samples. Think of Brewster angle of incidence of substrate also to investigate ultrathin film.
Thank you very much Michel !
I will consider all your recomendations
:)
If you don't have reliable optical constants of the film or/and the substrate, try to measure it from more than one angle-of-incident (AOI), then model thickness and the constants together at each wavelength with the combined data. Wavelength and AOI can be independently calibrated with a couple of know film structures.
Make sure the sample temperature are the same for different measurements. It matters for thin film at this level.
- Badges
- Science topic
- Similar topics
- Linguistics
- Composition Studies
- Publication