Effect of fluctuation in Al incorporation on the microstructure, bond lengths, and surface properties of an Al x Ga1−x N epitaxial layer

Wang, Shuchang; Zhang, Xiong; Yang, Hui; Cui, Yiping

doi:10.1007/s13391-015-4424-3

Cited by 5 publications

(6 citation statements)

References 33 publications

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“…Despite this observed difference in field strength, the species-specific trends in pair separation were consistent for ion pairs of both growth techniques. The pair separation for Ga-N ions did not appear to fluctuate with the transition from AlGaN to GaN, suggesting that Ga-N bond length is independent of Al content, which is in agreement with previous reports of Ga-N bond length in Al x Ga 1−x N (Wang et al, 2015). Initially, Al-N pairs appeared to demonstrate larger pair The dashed box on the left (orange) captures the co-evaporated events and the dashed box on the right (green) captures the dissociated events.…”

Section: Discussionsupporting

confidence: 92%

“…In the previous work by Wang et al,. Ga-Ga bond lengths demonstrated a dependence on Al content that aligned with predictions from Vegard's Law (Wang et al, 2015). The observed tendency for Ga-Ga pair separation to decrease within the Al 0.3 Ga 0.7 N layer agrees with the expected decrease in Ga-Ga bond length associated with increased Al content (Wang et al, 2015).…”

Section: Resultssupporting

confidence: 78%

“…Despite the variation in the field between the AlGaN and GaN layers, there is no significant variation in FWHM or median for Ga-N ion-pair separation in Figure 4. Previous reports on bond lengths in Al x Ga 1− x N from extended X-ray absorption fine structure spectroscopy demonstrated that Ga-N bond length is nearly independent of Al content (Wang et al, 2015). This would explain the limited variation in pair separation observed in Ga-N ion pairs between AlGaN and GaN layers.…”

Section: Resultsmentioning

confidence: 98%

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Understanding the Nature of Crystallographic Bonds by Establishing the Correlation between Ion-Pair Chemistry and Their Separation in Detector Space

Licata

Mazumder

2022

Microsc Microanal

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The occurrence of multi-hit events and the separation distance between multi-hit ion pairs field evaporated from III-nitride semiconductors can potentially provide insights on neighboring chemistry, crystal structure, and field conditions. In this work, we quantify the range of variation in major III-N and III-III ion-pair separation to establish correlations with bulk composition, growth method, and ion-pair chemistry. The analysis of ion-pair separation along the AlGaN/GaN heterostructure system allows for comparison of Ga-N and Ga-Ga ion-pair separation between events evaporated from pure GaN and Al0.3Ga0.7N. From this, we aim to define a relative measure for the bond length of ion pairs within an AlGaN/GaN heterostructure. The distributions of pair separation revealed a distinct bimodal behavior that is unique to Al-N2+ ion pairs, suggesting the occurrence of both co-evaporation and molecular dissociation. Finally, we demonstrated that the two modes of ion-pair events align with the known variation in the surface electric field of the AlGaN(0001) structure. These findings demonstrate the utility of atom probe tomography in studying the crystallographic nature of nitride semiconductors.

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Section: Discussionsupporting

confidence: 92%

Section: Resultssupporting

confidence: 78%

Section: Resultsmentioning

confidence: 98%

See 1 more Smart Citation

Understanding the Nature of Crystallographic Bonds by Establishing the Correlation between Ion-Pair Chemistry and Their Separation in Detector Space

Licata

Mazumder

2022

Microsc Microanal

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“…The peak position of GaN buffer layer is a constant, which corresponds to the GaN (0002) diffraction plane. The interplanar spacing of the epilayers can be determined by Bragg′s law:

where θ is diffraction angle, λ is the X-ray wavelength and d ( hkl ) is the distance between the crystal planes given by the Miller indices ( hkl ) [ 31 ]. The relationship between the interplanar spacing d along with (0001) orientation and the molar component x of ternary nitride alloy materials follows Vegard’s law:

where d (AlN) = 2.485 Å, d (GaN) = 2.593 Å [ 32 ].…”

Section: Resultsmentioning

confidence: 99%

Optical and Electrical Properties of AlxGa1−xN/GaN Epilayers Modulated by Aluminum Content

Wei,

Yang,

Peng

et al. 2024

Molecules

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AlGaN-based LEDs are promising for many applications in deep ultraviolet fields, especially for water-purification projects, air sterilization, fluorescence sensing, etc. However, in order to realize these potentials, it is critical to understand the factors that influence the optical and electrical properties of the device. In this work, AlxGa1−xN (x = 0.24, 0.34, 0.47) epilayers grown on c-plane patterned sapphire substrate with GaN template by the metal organic chemical vapor deposition (MOCVD). It is demonstrated that the increase of the aluminum content leads to the deterioration of the surface morphology and crystal quality of the AlGaN epitaxial layer. The dislocation densities of AlxGa1−xN epilayers were determined from symmetric and asymmetric planes of the ω-scan rocking curve and the minimum value is 1.01 × 109 cm−2. The (101¯5) plane reciprocal space mapping was employed to measure the in-plane strain of the AlxGa1−xN layers grown on GaN. The surface barrier heights of the AlxGa1−xN samples derived from XPS are 1.57, 1.65, and 1.75 eV, respectively. The results of the bandgap obtained by PL spectroscopy are in good accordance with those of XRD. The Hall mobility and sheet electron concentration of the samples are successfully determined by preparing simple indium sphere electrodes.

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“…Compared with conventional etching, atomic layer etching has many advantages in uniformity and high aspectratio structure etching. [19,20] In recent years, some techniques for etching GaN in atomic layers have been proposed, such as etching GaN by being exposed to Cl 2 and Ar alternately, [21] etching GaN by being exposed to O 2 and BCl 3 alternately, [22] but atomic layer etching has never been used to fabricate enhancement-mode high electron mobility transistors with a p-GaN gate.…”

Section: Introductionmentioning

confidence: 99%

Removal of GaN film over AlGaN with inductively coupled BCl₃/Ar atomic layer etch

Tang¹,

Liu²

2022

Chinese Phys. B

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In this work, atomic layer etching (ALE) of thin film GaN (0001) is reported in detail using sequential surface modification by BCl3 adsorption and removal of the modified surface layer by low energy Ar plasma exposure in a reactive ion etching system. The estimated etching rates of GaN were ~0.74 nm/cycle. The GaN was removed over AlGaN after 135 cycles. To study the mechanism of the etch, detailed characterization and analyses were carried out, including scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and atomic force microscope (AFM). It was found that in the presence of GaClx after surface modification by BCl3, the GaClx was disappeared after low energy Ar plasma exposure, which effectively ed the mechanism of atomic layer etch. This technique enables a uniform and reproducible fabrication process for enhancement-mode high electron mobility transistors with a p-GaN gate.

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Effect of fluctuation in Al incorporation on the microstructure, bond lengths, and surface properties of an Al x Ga1−x N epitaxial layer

Cited by 5 publications

References 33 publications

Understanding the Nature of Crystallographic Bonds by Establishing the Correlation between Ion-Pair Chemistry and Their Separation in Detector Space

Understanding the Nature of Crystallographic Bonds by Establishing the Correlation between Ion-Pair Chemistry and Their Separation in Detector Space

Optical and Electrical Properties of AlxGa1−xN/GaN Epilayers Modulated by Aluminum Content

Removal of GaN film over AlGaN with inductively coupled BCl₃/Ar atomic layer etch

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Effect of fluctuation in Al incorporation on the microstructure, bond lengths, and surface properties of an Al x Ga1−x N epitaxial layer

Cited by 5 publications

References 33 publications

Understanding the Nature of Crystallographic Bonds by Establishing the Correlation between Ion-Pair Chemistry and Their Separation in Detector Space

Understanding the Nature of Crystallographic Bonds by Establishing the Correlation between Ion-Pair Chemistry and Their Separation in Detector Space

Optical and Electrical Properties of AlxGa1−xN/GaN Epilayers Modulated by Aluminum Content

Removal of GaN film over AlGaN with inductively coupled BCl3/Ar atomic layer etch

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Product

Resources

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Removal of GaN film over AlGaN with inductively coupled BCl₃/Ar atomic layer etch