Dear colleague Uzair Majeed,

Have a nice time and good day.

1-Concerning your first question you can search on sciencedirect  and google about

"xrd of silicon nitride" i had found many results.

2-  Why the peaks are shifting?:  this means your sample undergoes some kind of micro-strain and also may has dislocations. so you need to calculate such this parameters.

I wish this is useful and help you.

Yours

A. El- Denglawey

Dear colleague Uzair Majeed,

Have a nice time and good day.

The attached paper will help and tech you easily  how to calculate micro-strain and also  dislocations.

I wish this is useful and help you.

Yours

A. El- Denglawey

Are these XRD scans grazing incidence? Your substrate is (100)-oriented, so if you do grazing incidence at 3 degrees incidence angle, you fulfill the Bragg condition for the (311) plane. For references, this is standard database (ICDD) material.

The SUBSTRATE is not strained, so the peak shift is not due to strain. Almost certainly, this is an alignment problem in your measurements, Please do a few of them again and see if you get the same result.

Also, relating to the previous answer: MICROstrain in a film causes peak broadening, not a peak shift. A peak shift in film would correspond to a macroscopic strain. 

I am getting same peak for grazing incidence at 0.35 or 0.5 incidence angle (for Si 100 wafers). This peak is "moving" between 51 and 53 2theta degree with a small bump after. There are two reasons for shift : the misalignement  of diffractometer and/or the tolerance of your wafer (+-0.05o) We are 4 degree far from Si 311 2theta - 56.13

Shift is almost certainly due to misalignement (I assume you align to the surface). To avoid this, you better align the substrate to the Si(400) peak (around 69.13 deg in 2theta for Cu_K_alpha). By this, you can align all your samples alike, independent of any potential miscut of the surface.

With thin films the misalignement is a common problem, so the shift is due to this problem

Thanks a lot guys for your contribution. Yes this is GI XRD scan. I will repeat experiment to focus on alignment. Thanks again

Dear colleagues , I have got another related post:

https://www.researchgate.net/post/Why_am_I_seeing_the_Si_311_peak_only_during_a_grazing_incidence_measurement

This confirms that at omega = 3 , 311 plane peak will appear at ~56o. However on less incident angles (omega) , the "tail" (less intensity) of peak will appear before 56o .

This explains the shift of peak in my spectra. The technician didnt fix the incidence angle. As she increased the angle towards omega = 3o, we can see an increase in intensity with peak shifting towards 56 degree.

Please comment.

Hi Uzair ..

I think maybe you need to get familiar with the XRD system in the lab especially parameters set for the 2Theta scan. Also the alignment of the sample including the z-axis.

If the sputtering process was not involved with high temperature, strain in not a major issue.

Maybe you can perform EDXS analysis to identify the compositions of the elements in every samples since this may contribute to the slight peak shifting as well.

Dear All

I want to one thing that as we find crystal size from XRD spectra but i am unable to understand what is the basic reason for the shift in peaks towards lower or higher angles (mechanism)

@ Neha Verma.

crystal sizes are not what you get from the 2theta position. What you get from 2theta diffraction scans is the interplanar spacings of the atomic structure: larger distances mean smaller 2theta angles, smaller distances mean larger 2theta angles.

For an easy estimation of crystallite(!) sizes in a sample you need to apply the Scherrer formula.