Silicon is crystalline solid with a diamond cubic crystal structure. Silicon wafers are frequently used as substrates for samples used in GISAXS. Si wafers make ideal substrates because they are very smooth at the atomic/nano scale, and are also very flat across larger (macroscale) distances. Note, however, that sample preparation (e.g. spin coating) may stress the wafer and 'kink' it, with effects that can be visible in GISAXS and especially reflectivity experiments.
Because silicon is normally a single-crystal, it leads to no discernible peaks on the detector unless the crystal lattice is aligned to satisfy the Bragg condition (i.e. the Ewald sphere must intercept a peak in the reciprocal lattice).
- Density: 2.3290 g/cm3
- Neutron SLD: 2.074×10−6 Å−2
|Material||density (g/cm3)||X-ray energy (keV)||X-ray wavelength (Å)||critical angle (°)||qc (Å−1)||SLD (10−6Å−2)|
Silicon is often used as a substrate. The transmission of a 'standard' (500 μm) Si wafer is:
|Material||density (g/cm3)||X-ray energy (keV)||X-ray wavelength (Å)||transmission|
- Wikipedia: Silicon
- Alexander Rack, Mario Scheel and Andreas N. Danilewsky Real-time direct and diffraction X-ray imaging of irregular silicon wafer breakage IUCrJ 2015 doi: 10.1107/S205225251502271X