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

Abstract

Defect reduction methods for III-nitride heteroepitaxial films grown along nonpolar and semipolar orientations P Vennéguès Defects in semipolar (11bar2bar2) ZnO grown on (112) LaAlO3/(La, Sr)(Al, Ta)O3 substrate by pulsed laser depositionWe have investigated the position dependence of crystalline quality and defect distribution in a semipolar ð2021Þ hydride vapor phase epitaxy (HVPE)-GaN film grown on a ð2243Þ patterned sapphire substrate (PSS). Position-dependent X-ray microdiffraction (XRMD) measurement clearly revealed the periodic fluctuation of the 20 21 lattice plane tilting in HVPE-GaN films. This correlated with the periodic distribution of (a + c)-type dislocations owing to the patterning pitch of the PSS as confirmed by transmission electron microscopy (TEM). In the three-dimensional reciprocal lattice space map, the diffuse streak exactly along the c-axis can be clearly detected, indicating the presence of basal plane stacking faults in HVPE-GaN films. Furthermore, we have quantitatively estimated the defect densities from the results of XRMD and TEM measurements. From the obtained results of XRMD and TEM measurements, the fluctuation of the lattice plane tilting and the defect distribution in ð2021Þ HVPE-GaN films grown on two types of metalorganic vapor phase epitaxy-GaN templates will be discussed in detail.

Local strain distribution analysis in strained SiGe spintronics devices

“…The standard values of the lattice constants used in the strain calculations were adopted from the literature; the lattice constant for Si, a Si = 5.43105 Å, and for Ge, a Ge = 5.6575 Å. 24) We obtained the Ge content from the twodimensional reciprocal space mapping and calculated the strain at each measurement point by using the Vegard's law To evaluate the crystallinity, the integral breadths β of 2θ profiles, corresponding to lattice spacing fluctuation, and ω profiles, lattice tilting fluctuation, were defined as shown in the following equations 25) ( ) b = integrated intensity of the profile maximum intensity . 5…”

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

“…In recent years, 3D-RSM analysis 13) in combination with XRMD 14,15) has been increasingly applied to NS films. The 3D-RSM analysis of semipolar ð20…”

“…21Þ GaN thick films grown on patterned sapphire substrates has enabled the quantitative clarification of the 3D anisotropic microstructural fluctuations and position-dependent defect density with high spatial resolution. 15) In particular, the periodic and microscopic distributions of basal plane stacking faults (BSFs) in GaN films have been successfully revealed on the basis of this technique by the detection of 3D diffuse streaks due to BSFs.…”

“…The diffracted X-ray microbeam (K) was acquired with a 2D-CCD detector. The incident angle was varied and the 2D-CCD detector was used to construct 3D-RSMs and ω-2θ-φ maps, 15) where ω is the lattice plane tilt, θ is the Bragg angle corresponding to the lattice spacing, and φ is the lattice plane twist, and these maps reflect the 3D microscopic crystallinity for each sampling position.…”