X-ray analysis of the texture of heteroepitaxial gallium nitride films

The study of GaN morphology and structure modification due to the variation of the nitridation temperature are reported. GaN is obtained by nitridation of GaAs (1 1 1) using the flow of a mixture of hydrogen and ammonia into a horizontal CVD system. The experiments are carried out at atmospheric pressures of 800, 900, and 1000°C for 1 h. XRD results together with the pole figure indicate that GaN (1-x) As x is obtained at 800°C, that zinc-blende GaN structure is obtained at 900°C, and that wurtzite GaN structure is obtained at 900°C. The photoluminescence emission peak (obtained at room temperature) shifts to 420, 384, and 372 nm with the nitridation temperature change, in agreement with the XRD and pole figure results. SEM images show the morphology change, where GaN (1−x) As x and GaN layers are obtained at 800 and 900°C, respectively, while GaN columns are obtained at 1000°C. The morphology and structure change due the nitridation temperature variation are also discussed based on the results.

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“…Figure b shows the z‐GaN peak at 2θ = 40°. Relating this result to the XRD result, it can be concluded that the preferential structure is z‐GaN …”

Section: Resultsmentioning

confidence: 74%

“…On the other hand, Figure b does not show the z‐GaN structure at ψ = 0°. The peaks around ψ = 30° are under study, but they could be related to GaN (1‐x) As x …”

Section: Resultsmentioning

confidence: 99%

Fabrication of GaN_(1−x)As_x, Zinc‐Blende, or Wurtzite GaN Depending on GaAs Nitridation Temperature in a CVD System

Ramírez-González

Garcı́a-Salgado

Morales

et al. 2018

Crystal Research and Technology

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“…For example, the wurtzite 0 0 0 2 wz and zincblende 1 1 1 zb reflections, which both occur for 2θ ≈ 34.5° are unsuitable, as are the wurtzite 1 1 2 0 wz and the zincblende 2 2 0 zb reflections (2θ ≈ 57.8°). Herres et al proposed the use of the cubic 2 0 0 zb (2θ ≈ 40.0°) and the hexagonal 1 0 1 2 wz (2θ ≈ 48.1°) reflections for predominantly (1 1 1) zb and (0 0 0 1) wz oriented films respectively, which has been shown to give reasonable results [24]. However, for predominantly (0 0 1) zb oriented cubic films one should rather use different zincblende reflections, as the reflections from the {1 0 0} zb side facets are often very weak and superimposed with surface scattering effects, making the identification of the in-plane epitaxial relations of the films difficult.…”

Section: Polytype Identificationmentioning

confidence: 99%

X-ray diffraction analysis of cubic zincblende III-nitrides

Frentrup

Lee

Sahonta

et al. 2017

J. Phys. D: Appl. Phys.

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Solving the green gap problem is a key challenge for the development of future LED-based light systems. A promising approach to achieve higher LED efficiencies in the green spectral region is the growth of III-nitrides in the cubic zincblende phase. However, the metastability of zincblende GaN along with the crystal growth process often lead to a phase mixture with the wurtzite phase, high mosaicity, high densities of extended defects and point defects, and strain, which can all impair the performance of light emitting devices. X-ray diffraction (XRD) is the main characterization technique to analyze these device-relevant structural properties, as it is very cheap in comparison to other techniques and enables fast feedback times. In this review, we will describe and apply various XRD techniques to identify the phase purity in predominantly zincblende GaN thin films, to analyze their mosaicity, strain state, and wafer curvature. The different techniques will be illustrated on samples grown by metalorganic vapor phase epitaxy on pieces of 4″ SiC/Si wafers. We will discuss possible issues, which may arise during experimentation, and provide a critical view on the common theories.

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“…The physical properties of the epitaxial layers depend on structural features like phase purity, mosaicity, strains and chemical composition. In two earlier papers we addressed problems related to polytypism and texture (Herres et al, 1999) and presented an X-ray diffraction technique suited for the rapid determination of the state of strain and the composition of partially relaxed Al x Ga 1Àx N and Ga 1Àx In x N layers (Herres et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Analysis of the mosaic structure of an ordered (Al,Ga)N layer

Kirste¹,

Pavlov²,

Mudie³

et al. 2005

J Appl Cryst

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The mosaic structure of an (Al, Ga) N layer grown on (0001) sapphire showing natural ordering was studied by high-resolution X-ray diffraction (HRXRD) reciprocal-space mapping. The direction-dependent mosaicity of the layer has been elaborated using maps of symmetrical and asymmetrical reflections. The reciprocal-lattice points show significant broadening depending on the direction in reciprocal space, the diffraction order and the reflection type ( fundamental or superstructural). The evaluation followed two paths: (i) a procedure based on the Williamson - Hall plot and (ii) a new approach based on the statistical diffraction theory (SDT). Here, the transformed Takagi equations were implemented for the simulation of the reciprocal-space maps (RSM) for symmetrical and asymmetrical reflections. The reconstruction comprised the mosaic block size, their average rotation angle and the spatial distribution of some components of the microdistortion tensor. The results based on the SDT modelling agree well with those obtained by the Williamson - Hall method, while providing a higher degree of precision and detail

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X-ray analysis of the texture of heteroepitaxial gallium nitride films

Cited by 14 publications

References 7 publications

Fabrication of GaN_(1−x)As_x, Zinc‐Blende, or Wurtzite GaN Depending on GaAs Nitridation Temperature in a CVD System

Fabrication of GaN_(1−x)As_x, Zinc‐Blende, or Wurtzite GaN Depending on GaAs Nitridation Temperature in a CVD System

X-ray diffraction analysis of cubic zincblende III-nitrides

Analysis of the mosaic structure of an ordered (Al,Ga)N layer

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X-ray analysis of the texture of heteroepitaxial gallium nitride films

Cited by 14 publications

References 7 publications

Fabrication of GaN(1−x)Asx, Zinc‐Blende, or Wurtzite GaN Depending on GaAs Nitridation Temperature in a CVD System

Fabrication of GaN(1−x)Asx, Zinc‐Blende, or Wurtzite GaN Depending on GaAs Nitridation Temperature in a CVD System

X-ray diffraction analysis of cubic zincblende III-nitrides

Analysis of the mosaic structure of an ordered (Al,Ga)N layer

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Fabrication of GaN_(1−x)As_x, Zinc‐Blende, or Wurtzite GaN Depending on GaAs Nitridation Temperature in a CVD System

Fabrication of GaN_(1−x)As_x, Zinc‐Blende, or Wurtzite GaN Depending on GaAs Nitridation Temperature in a CVD System