When measuring by GIXRD (grazing angle=0.3 or 0.5 deg), using Cu radiation, at 50.83, respectively 51.28 deg, a sharp diffraction line followed by a broad line (53-56 deg) from Si-based substrate is detected.
What atomic plane of Si (100) or Si (111) or SiO2 is located at the 2 theta mentioned above? The sample was annealed at 400 C deg.
I guess you used Cu radiation? Without this information one cannot tell anything, only speculate :-).
At room temperature the attached peaks appear. Surprisingly there is no good match for Si. For SiO2 I assumed quartz, but maybe other modifications show a better agreement. Which modification do you assume?
Thank you!
I assume that the line at 51.26 deg corresponds to (112) plane of SiO2 - quartz that formed a thin film on Si surface. Displacement can be due to strain induced by the Si substrate and the nanometric dimension of the crystals.
Not sure about the line a 53.46 deg. Displacement is too high to be the (003) plane of quartz and no plane of Si matches.
003 is too far away. Anyway, please try to differentiate between Laue indexing for reflexes (NO brackets) and lattice planes (parenthesis). (001) ist the lattice plane, 001 is the first order interference of lattice plane (001), 002 second order etc. They correspond to points in reciprocal space whereas (001) defines the deriction in reciprocal space containing all lattice points.
Do you expect other phases (tridymite, cristobalite etc ) ?
Beside the thin film crystalline phases, deposited on Si wafer, these lines also appeared. No match with the thin film phases, Si or SiO2 could be done. Can be assigned only to the substrate, because they appeared on the blank/uncovered silicon wafer diffractogram. Only a silicon oxide can crystallize on the surface of the wafer, but I wasn t able to assign it. Thank you again
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