I have metallic thinfilm of 30 nm in thickness with bi-axial texture shown by SEM at cross section. However I faced some difficulties in XRD. During pole scan when psi angle tend to 90 degree and x-ray mostly hits the film not substrate, this is important part of my pole figure. But the signal is very poor because x-ray then get defocused. I just find something about the result should be multiplied by a factor to compensate the defocuse but no number in the literature. It may seems silly but I also did pole scan in grazing incidence configuration and I still do not have any meaningful signal. The xrd machine is high resolution in plane and in all angles which very well calibrated every time around substrate peak. Pole figures obtained at three peaks of thinfilm which already obtained in GIXRD. Does anybody have idea around this subject? I really appreciate any help in advance.
Thank you for your answer. I am always using parallel beam and I tried 1/2 - 1/32 beam slit for that. The bigger slit gives stronger signal but signal to background ratio decreases.
If you really want measure a 30nm thick layer only, your x-ray beam practically does not see anything since the major information comes from the deeper volume (in the scale of microns). You don't write anything about the material but even for gold I would not expect any signal. Therefore, gracing incident is actually the correct choice, or you measure with high psi angle, but then your slit system does not match. You could rotate your tube to point focus and use a hole aperture as typical for texture or residual stress.
If you don't get any suitable signal...you perhaps should think about another technique like EBSD. If you see the grains in SEM the resolution is obviously sufficient. How big is the grain size?
Thank you Gert and sorry for insufficient info. I have 30 nm Ni80Fe20 layer (detected by XRR and AFM) on 100 nm SiO2 thermally grown on Si (001). I am using a Dutch designed PANalytical system. I couldn't see grains in the SEM but cross section shows the biaxial pattern. However, the grain size from Scherrer equation obtained ~6 nm.
I don't think the Ni signal might be stronger than Au in electron density. So I agree that GIXRD should be the best. I was wondering If we don't get meaningful signal in normal XRD, how people use this configuration for showing epitaxial metallic nanofilms? In the literature they discuss how ex. Ni point sites on the substrate points in the pole figure while they don't have Ni signal.
The hole aperture instead of slit seem a good idea. But reflection of a slit or hole at psi 90 degree should be the same. Am I right?
I also had another question in area of your expertise Gerts. Could you please teach me how to calibrate at different psi values? I think I need to do several pole scan with small Psi range and re-calibrate each time.
I strongly hope that your Panalytical software automatically corrects the intensities.
If you will use a hole aperture the angular resolution decreases, but for texture measurements this is not important. You know the Bragg angle, and for Texture measurements you are only interested in the directional distribution. But I guess that in several papers it is well described how to perform texture measurements with GIXRD.
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