Reconstruction of crystal shapes by X-ray nanodiffraction from three-dimensional superlattices

Abstract

Quantitative nondestructive imaging of structural properties of semiconductor layer stacks at the nanoscale is essential for tailoring the device characteristics of many low‐dimensional quantum structures, such as ultrafast transistors, solid state lasers and detectors. Here it is shown that scanning nanodiffraction of synchrotron X‐ray radiation can unravel the three‐dimensional structure of epitaxial crystals containing a periodic superlattice underneath their faceted surface. By mapping reciprocal space in all three dimensions, the superlattice period is determined across the various crystal facets and the very high crystalline quality of the structures is demonstrated. It is shown that the presence of the superlattice allows the reconstruction of the crystal shape without the need of any structural model.

Lattice tilt and strain mapped by X-ray scanning nanodiffraction in compositionally graded SiGe/Si microcrystals

“…5(a)-5(k), the diffraction signal from the compositionally graded SiGe crystal is represented as three-dimensional curves in ðQ x ; Q y ; Q z Þ reciprocal space. Owing to the optical resolution function of the setup in Q space, the rod-shaped maximum of a perfect crystal assumes a cylindrical form (Meduň a et al, 2014). For the nearly perfect narrow LG2 crystal with L 1 = 2 mm, the diffracted intensity maximum is just such a short, practically straight, cylinder mostly oriented along the Q x direction.…”

“…The focusing of an X-ray beam is possible even down to 5 nm (Mimura et al, 2010;Krü ger et al, 2012;Dö ring et al, 2013). During the past ten years, several authors have investigated, for instance, the local strain in thin films (Murray et al, 2005), the shape and strain of individual nanostructures (Hanke et al, 2008;Mocuta et al, 2008;Diaz et al, 2009;Biermanns et al, 2013;Bussone et al, 2015), the mosaicity of graded layers (Bartosik et al, 2013;Stefenelli et al, 2013), individual electronic devices (Hrauda et al, 2011;Paci et al, 2013), the structure of magnetic domains (Schmidbauer et al, 2017), the shape of defects in heteroepitaxial microstructures (Meduň a et al, 2014), and high-resolution mapping of lattice bending and strain inside various layers (Mondiali, Bollani Wallentin et al, 2016) with nanoscale resolution. An important recent improvement of SXDM is scanning nanodiffraction with continuous motion, which allows more efficient data collection (Chahine et al, 2014).…”

Lattice bending in three-dimensional Ge microcrystals studied by X-ray nanodiffraction and modelling

“…The energy of the X-ray photons was 11.07 keV. Thus, the nanofocused X-ray beam, together with the high-precision x-y translational piezo-stage, allows scanning of individual microcrystals (Falub et al, 2013;Meduň a et al, 2014). This technique is called scanning X-ray diffraction microscopy (SXDM) (Stangl et al, 2009;Chahine et al, 2014).…”

“…The development of focusing optics for X-ray beams has, for instance, permitted the measurement of the strain in thin films (Murray et al, 2005), the shape of individual quantum dots (Hanke et al, 2008), the strain inside individual quantum dots (Diaz et al, 2009;Mocuta et al, 2008) or inside nanorods (Biermanns et al, 2013), the mosaicity of graded layers (Bartosik et al, 2013;Stefenelli et al, 2013), and individual electronic devices (Hrauda et al, 2011;Paci et al, 2013), all at the nanoscale. Moreover, scanning diffraction with a focused X-ray beam has been shown to be an appropriate technique to map the lattice strain and individual defects in heteroepitaxial microstructures (Meduň a et al, 2014). Very recently, the implementation of fast scanning nanodiffraction with continuous motion was introduced by Etzelstorfer et al (2014) and Chahine et al (2014).…”

Strain relaxation in Ge microcrystals studied by high‐resolution X‐ray diffraction

“…The growth technique has been tested with different material combinations and substrate orientations . The quasi‐continuous Ge epilayers studied in this paper have a large application potential as X‐ray absorbers monolithically integrated onto CMOS readout circuits or as virtual substrates for the epitaxial growth of other semiconductor materials with similar lattice parameters, such as GaAs ().…”