Mosaic Structure Characterization of the AlInN Layer Grown on Sapphire Substrate

Abstract

The 150 nm thick, (0001) orientated wurtzite-phase Al1−xInxN epitaxial layers were grown by metal organic chemical vapor deposition on GaN (2.3 µm) template/(0001) sapphire substrate. The indium (x) concentration of the Al1−xInxN epitaxial layers was changed as 0.04, 0.18, 0.20, 0.47, and 0.48. The Indium content (x), lattice parameters, and strain values in the AlInN layers were calculated from the reciprocal lattice mapping around symmetric (0002) and asymmetric (10–15) reflection of the AlInN and GaN layers. The mosaic structure characteristics of the AlInN layers, such as lateral and vertical coherence lengths, tilt and twist angle, heterogeneous strain, and dislocation densities (edge and screw type dislocations) of the AlInN epilayers, were investigated by using high-resolution X-ray diffraction measurements and with a combination of Williamson-Hall plot and the fitting of twist angles.

Effects of the AlN nucleation layer thickness on the crystal structures of an AlN epilayer grown on the 6H-SiC substrate

“…The hexagonal III-nitride based materials grown on foreign substrates have a mosaic structure [27][28][29][30][31][32][33][34]. The crystallographic c-axis of III-nitride based epilayer mosaic columns and the c-direction of the substrate coincided with a small angle and, therefore, the lattice constants of a and b of the hexagonal epilayer are oriented parallel to the z-plane of the substrate [27][28][29][30][31][32][33][34]. In our case, therefore, the AlN epilayer exhibits in-plane isotropic elastic properties, and its in-plane lattice deformation states can be defined with one strain parameter.…”

“…In our case, therefore, the AlN epilayer exhibits in-plane isotropic elastic properties, and its in-plane lattice deformation states can be defined with one strain parameter. The in-plane (1 xx ) and out-of-plane (1 zz ) strain components in the AlN epilayers can be calculated using the crystal lattice constants a and c, respectively [27,28,30,[35][36][37][38].…”

“…The crystal lattice constants (a and c) of the hexagonal crystal structures can be precisely calculated using symmetric and skew symmetric ω−2θ scans of the [27,28,30,35]. There are two unknowns in these equations.…”

“…There are two unknowns in these equations. For this reason, we need at least two different plane reflections (d hkl ) measurements in the calculation study of a and c parameters [27,28].…”

Analysis of the Mosaic Defects in Graded and Non Graded In_xGa_1-xN Solar Cell Structures

“…Because of the applications at light emitting diodes (LEDs), laser diodes and light sensors, AlN, GaN, InN and the III-N material system containing these have a wide usage [1,2]. Meanwhile the band range of the InN alloy and the band range of the InGaN material reach almost respectively 0.65 eV from infrared to the ultraviolet areas [3][4][5].…”