Atomic structure analysis of gallium oxide at the Al<sub>2</sub>O<sub>3</sub>/GaN interface using photoelectron holography

Uenuma, Mutsunori; Kuwaharada, Shingo; Tomita, Hideharu; Tanaka, Masaki; Sun, Zexu; Hashimoto, Yusuke; Fujii, Mami N.; Matsushita, Teruo; Uraoka, Yukiharu

doi:10.35848/1882-0786/ac7dd9

Cited by 5 publications

(3 citation statements)

References 36 publications

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“…Surface etching was performed in the chamber by using Ar ion milling. Photoelectron holography, a type of atomic resolution holography that can directly reveal a three-dimensional local structure around a target atom [ 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 ], was performed by using soft X-ray as a light source at the beamline 25SU [ 64 ] of the synchrotron radiation facility Super Photon ring-8 GeV (SPring-8), Japan. A wide-angle display-type retarding field analyser was used for the measurement [ 65 ].…”

Section: Calculation and Experimental Methodsmentioning

confidence: 99%

Effects of Oxygen on Lattice Defects in Single-Crystalline Mg2Si Thermoelectrics

et al. 2023

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Lattice defect engineering has attracted attention due to its ability to develop thermoelectric materials with low thermal conductivity. For Mg2Si single crystals (SCs), Si vacancy (VSi) defects can be introduced and consequently result in the formation of dislocation cores. These lattice defects confer Mg2Si SCs with a lower thermal conductivity compared to Mg2Si polycrystals. To reveal a mechanism for the stabilisation of VSi in the Mg2Si SCs, we investigated the effects of oxygen (O) on lattice defects by performing electronic structure calculations, secondary ion mass spectrometry, X-ray photoelectron spectroscopy, and photoelectron holography. On the basis of these calculations, we predicted that O stabilised the formation of VSi when it was located at the Si site or at an interstitial site. All experiments confirmed the presence of O inside the Mg2Si SCs. However, O was suggested to be located not at the specific site in the crystal lattice of Mg2Si but at dislocation cores. The interaction between O and the dislocation cores in the Mg2Si SC is expected to immobilise dislocation cores, leading to the stabilisation of VSi formation.

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Section: Calculation and Experimental Methodsmentioning

confidence: 99%

Effects of Oxygen on Lattice Defects in Single-Crystalline Mg2Si Thermoelectrics

et al. 2023

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“…While various process techniques have already been established for silicon semiconductors, process development is still required for wide-band-gap semiconductors. In this study, our objectives are GaN power semiconductor devices, which have attracted much attention in recent years, while many issues still remain at the MOS interface. , One of the challenges is how to reduce the electrical interface defects measured by the interface state density, D it , which represents the quality of an interface. D it is strongly affected by the surface condition of the GaN substrate and the deposition conditions of plasma-enhanced chemical vapor deposition (PECVD), which deposits SiO 2 .…”

Section: Introductionmentioning

confidence: 99%

Interface State Density Prediction between an Insulator and a Semiconductor by Gaussian Process Regression Models for a Modified Process

Matsunaga

Harada

et al. 2023

ACS Omega

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During data-driven process condition optimization on a laboratory scale, only a small-size data set is accessible and should be effectively utilized. On the other hand, during process development, new operations are frequently inserted or current operations are modified. These accessible data sets are somewhat related but not exactly the same type. In this study, we focus on the prediction of the quality of the interface between an insulator and GaN as a semiconductor for the potential application of GaN power semiconductor devices. The quality of the interface was represented as the interface state density, D it, and the inserted operation to the process was the ultraviolet (UV)/O3-gas treatment. Our retrospective evaluation of model-building approaches for D it prediction from a process condition revealed that for the UV/O3-treated interfaces, data of interfaces without the treatment contributed to performance improvement. Such performance improvement was not observed when using a data set of Si as the semiconductor. As a modeling method, the automatic relevance vector-based Gaussian process regression with the prior distribution of the length-scale parameters exhibited a relatively high predictive performance and represented a reasonable uncertainty of prediction as reflected by the distance to the training data set. This feature is a prerequisite for a potential application of Bayesian optimization. Furthermore, hyperparameters in the prior distribution of the length-scales could be optimized by leave-one-out cross-validation.

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“…PEH has a great advantage in which nonperiodic atomic structures are applicable. Additionally, since PEH is based on photoelectron spectroscopy, chemical-state-discriminated PEHs can be achieved. − Therefore, we can clarify the atomic structures and chemical states of the Si dopants in κ-Ga 2 O 3 . The PEH schematic is shown in Figure (b).…”

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confidence: 99%

Photoelectron Holographic Study for Atomic Site Occupancy for Si Dopants in Si-Doped κ-Ga₂O₃(001)

Tsai,

Hashimoto,

Sun

et al. 2024

Nano Lett.

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We investigated atomic site occupancy for the Si dopant in Si-doped κ-Ga 2 O 3 (001) using photoelectron spectroscopy (PES) and photoelectron holography (PEH). From PES and PEH, we found that the Si dopant had one chemical state, and three types of inequivalent Si substitutional sites (Si Ga ) were formed. The ratios for the inequivalent tetrahedral, pentahedral, and octahedral Si Ga sites were estimated to be 55.0%, 28.1%, and 16.9%, respectively. Higher (lower) ratios for the three inequivalent Si Ga sites may come from a lower (higher) formation energy. The Tetra (Octa) Si Ga site has the highest (lowest) ratio of the three Si Ga sites since it has the lowest (highest) formation energy. We suggest that the tetrahedral Si Ga site is due to the active dopant site, whereas the pentahedral and octahedral Si Ga sites can be attributed to the inactive dopant sites for Si-doped κ-Ga 2 O 3 (001).

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Atomic structure analysis of gallium oxide at the Al₂O₃/GaN interface using photoelectron holography

Cited by 5 publications

References 36 publications

Effects of Oxygen on Lattice Defects in Single-Crystalline Mg2Si Thermoelectrics

Effects of Oxygen on Lattice Defects in Single-Crystalline Mg2Si Thermoelectrics

Interface State Density Prediction between an Insulator and a Semiconductor by Gaussian Process Regression Models for a Modified Process

Photoelectron Holographic Study for Atomic Site Occupancy for Si Dopants in Si-Doped κ-Ga₂O₃(001)

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Atomic structure analysis of gallium oxide at the Al2O3/GaN interface using photoelectron holography

Cited by 5 publications

References 36 publications

Effects of Oxygen on Lattice Defects in Single-Crystalline Mg2Si Thermoelectrics

Effects of Oxygen on Lattice Defects in Single-Crystalline Mg2Si Thermoelectrics

Interface State Density Prediction between an Insulator and a Semiconductor by Gaussian Process Regression Models for a Modified Process

Photoelectron Holographic Study for Atomic Site Occupancy for Si Dopants in Si-Doped κ-Ga2O3(001)

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Atomic structure analysis of gallium oxide at the Al₂O₃/GaN interface using photoelectron holography

Photoelectron Holographic Study for Atomic Site Occupancy for Si Dopants in Si-Doped κ-Ga₂O₃(001)