Effects of Al doping on dislocation inclinations and strain of GaN films on Si substrates

Zhang, Jie; Yang, Xuelin; Ma, Hong-Ping; Zhang, Qingchun; Shen, Bo

doi:10.1063/5.0126796

Cited by 3 publications

(2 citation statements)

References 34 publications

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“…The reason for this is that the recent theoretical calculations have shown that the concentration of tri-carbon complexes exceeds that of C N at C doping concentrations higher than ∼10 18 cm −3 . 31) In addition, the C N -C Ga -C N complexes explained by the DFT calculations have been reported to exhibit behavior similar to that of the isolated C N acceptor, with transition levels of ∼0.55 eV. 22,28) Although our experimental carrier trap level is not in agreement with the calculated one, it is relatively close to that of the C N -C Ga -C N complexes compared to other tri-carbon complexes that have deeper transition levels above 1 eV.…”

Section: Resultsmentioning

confidence: 99%

Investigation of carbon-related complexes in highly C-doped GaN grown by metalorganic vapor phase epitaxy

Honda,

Watanabe,

Takeuchi

et al. 2024

Jpn. J. Appl. Phys.

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We investigated the C-related complexes in highly C-doped GaN by electron spin resonance (ESR) spectroscopy, Fourier transform infrared spectroscopy (FTIR), and minority carrier transient spectroscopy (MCTS) measurements. In the ESR spectra, two resonances with g values of 2.02 and 2.04 were found to be assigned by (0/-) deep acceptor and (+/0) charge transition levels of carbon substituting for nitrogen site (CN). In the FTIR spectra, two local vibrational modes positioned at 1679 and 1718 cm-1 were confirmed to be associated with tri-carbon complexes of CN-CGa-CN (basal) and CN-CGa-CN (axial), respectively. In the MCTS spectra, we observed the hole trap level of Ev + 0.25 ± 0.1 eV associated with the tri-carbon complexes, which are the dominant C-related defects, suggesting that these complexes affect the electronic properties in the highly C-doped GaN.

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Section: Resultsmentioning

confidence: 99%

Investigation of carbon-related complexes in highly C-doped GaN grown by metalorganic vapor phase epitaxy

Honda,

Watanabe,

Takeuchi

et al. 2024

Jpn. J. Appl. Phys.

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“…Eventually, the length of the bent segment of the TDs becomes equal to the length of the misfit segment, leading to a decrease in the elastic strain energy and, therefore, a reduction in dislocations, − resulting in a higher crystalline quality. While the use of strain has been utilized by many researchers − to reduce dislocations, it is important to note that the strain profile should be chosen wisely. When compared to a sharp strain boundary, a linear strain gradient offers TDs the opportunity to reduce the energy of the system more by leaving the system than by propagating into the strained region.…”

Section: Resultsmentioning

confidence: 99%

Improved Quality of InN Thin Films Using a Thin InGaN Compressive Strain Gradient Layer

Shetty,

Kuchuk,

Maia de Oliveira

et al. 2024

Crystal Growth & Design

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High-quality InN has significant opportunities for exciting and impactful electronic and photonic applications. These applications rely on growth techniques that produce high-quality InN thin films. To achieve the fabrication of InN semiconductor thin films with a low density of misfit and threading dislocations, we report on a growth technique that utilizes composition and strain gradients to limit the propagation of defects into InN grown on a GaN/sapphire substrate. The growth technique we have investigated utilizes a compressively strained gradient transition layer to limit the propagation of threading dislocations from the GaN buffer. Reflection high-energy electron diffraction, high-resolution X-ray diffraction, Raman spectroscopy, photoluminescence, and Hall measurements were employed to evaluate the effectiveness of the gradient transition layer to improve the quality of InN thin films. The outcome is that for InN films grown on partially graded In x Ga 1−x N (x → 0 to 29%), when compared with InN grown directly on a GaN substrate, we observed about a 40% decrease in edge dislocations, a 50% increase in photoluminescence, and a 20% increase in mobility. When compared to a sharp strain boundary, a linear strain gradient offers threading dislocations the opportunity to reduce the energy of the system more by leaving the system than by propagating into the strained region.

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Investigation of the Dislocation Behavior of 6- and 8-Inch AlGaN/GaN HEMT Structures with a Thin AlGaN Buffer Layer Grown on Si Substrates

Yan,

Huang,

Pan

et al. 2024

Inorganics

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Developing cost-effective methods to synthesize large-size GaN films remains a challenge owing to the high dislocation density during heteroepitaxy. Herein, AlGaN/GaN HEMTs were grown on 6- and 8-inch Si(111) substrates using metal–organic chemical vapor deposition, and their basic properties and dislocation evolution characteristics were investigated thoroughly. With the insertion of a 100 nm thin AlGaN buffer layer, bow–warp analysis of the epitaxial wafers revealed excellent stress control for both the 6- and 8-inch wafers. HR-XRD and AFM analyses validated the high crystal quality and step-flow growth mode of GaN. Further, Hall measurements demonstrated the superior transport performance of AlGaN/GaN heterostructures. It is worth noting that dislocations tended to annihilate in the AlN nucleation layer, the thin AlGaN buffer layer, and the GaN buffer layer in the initial thickness range of 200–300 nm, which was indicated by ADF-STEM. To be specific, the heterointerfaces exhibited a significant effect on the annihilation of c-type (b = <0001>) dislocations, which led to the formation of dislocation loops. The thin inserted layers within the AlGaN buffer layer played a key role in promoting the annihilation of c-type dislocations, while they exerted less influence on a-type (b = 1/3<112¯0>) and (a+c)-type (b = 1/3<112¯3>) dislocations. Within an initial thickness of 200–300 nm in the GaN buffer layer, a-type and (a+c)-type dislocations underwent strong interactions, leading to considerable dislocation annihilation. In addition, the EELS results suggested that the V-shaped pits in the AlN nucleation layer were filled with the AlGaN thin layer with a low Al content.

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Effects of Al doping on dislocation inclinations and strain of GaN films on Si substrates

Cited by 3 publications

References 34 publications

Investigation of carbon-related complexes in highly C-doped GaN grown by metalorganic vapor phase epitaxy

Investigation of carbon-related complexes in highly C-doped GaN grown by metalorganic vapor phase epitaxy

Improved Quality of InN Thin Films Using a Thin InGaN Compressive Strain Gradient Layer

Investigation of the Dislocation Behavior of 6- and 8-Inch AlGaN/GaN HEMT Structures with a Thin AlGaN Buffer Layer Grown on Si Substrates

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