Microscopic crystalline structure of a thick AlN film grown on a trench-patterned AlN/α-Al2O3 template

Positional dependence of defect distribution in semipolar hydride vapor phase epitaxy-GaN films grown on patterned sapphire substrates

“…13) 21 lattice plane. We previously reported that this feature was also observed in the MOVPE-GaN template before HVPE-GaN growth.…”

“…An X-ray microdiffraction (XRMD) system using a synchrotron radiation source is one of the most appropriate characterization tools having a submicrometer-scale X-ray probe to characterize microscopic crystalline properties. [10][11][12][13][14][15] Using a two-dimensional reciprocal lattice space map (2D-RSM) obtained by XRMD analysis, we have recently clarified the microscopic distributions and fluctuations of strain and the lattice plane microstructure in epitaxial nitride semiconductor thick films grown on patterned substrates. 13,14) For example, in ð20 " 21Þ MOVPE-GaN films grown on a ð22 " 43Þ PSS, the results clearly showed that the fluctuation of 20 " 21 lattice plane tilting in the MOVPE-GaN films was strongly affected by the patterning pitch and structure of the PSS.…”

Microstructural analysis of an epitaxial AlN thick film/trench-patterned template by three-dimensional reciprocal lattice space mapping technique

“…On the other hand, inhomogeneous strain and microstructures of lattice planes are also introduced into an NS film, which are often coincident with the patterning pitch of the substrate and resultant void arrangement. 8) Such inhomogeneity is considered to cause variations in the electrical and optical properties of an NS film.…”

“…A two-dimensional reciprocal lattice space map (2D-RSM) analysis combined with an X-ray microdiffraction (XRMD) technique using a sub-micrometer-scale focused X-ray beam (X-ray microbeam) is a promising method of achieving this and has been recently used for the characterization of various types of NS films. [8][9][10][11][12] To reveal the 3D structures of the lattice, 2D-RSM measurements must be performed for the exact same sampling position using at least two different asymmetric Bragg reflection planes that are not parallel to each other. In our previous work on an epitaxial AlN thick film grown on a trench-patterned AlN=sapphire template, we attempted to characterize 3D microstructures using a combination of two different 2D-RSM analyses for the same sampling position in the cross-sectional XRMD analysis.…”

“…The microstructure and domain texture are known to have a close relationship with the distribution and type of dislocations in NS films. 8,18) Dislocations with a c component and those with an a component propagating in the [0001] direction generally induce ð2 201Þ lattice plane tilt and twist, respectively. The TEM analysis of wide areas of the sample indicated that the distribution and morphology of dislocations in the AlN film have a periodic nature, as determined by the patterning pitch of the template.…”