Band alignment of SiO2/(Al Ga1-)2O3 (0 ≤x≤ 0.49) determined by X-ray photoelectron spectroscopy

Feng, Zhaoqing; Feng, Qian; Zhang, Jincheng; Li, Xiang; Li, Fuguo; Huang, Lu; Chen, Liqun; Lü, Hongliang; Hao, Yue

doi:10.1016/j.apsusc.2017.10.156

Cited by 41 publications

(44 citation statements)

References 25 publications

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“…Conduction band offsets of at least 1.4 eV for all compositions provide excellent carrier confinement for electrons exceeding the required 1 eV recommended in literature for MOS transistors 59 . The magnitude of these offsets is similar to those of established dielectrics such as SiO2, Al2O3, HfO2 or HfSiO4 to various other polymorphs of the (AlxGa1-x)2O3/(InxGa1x)2O3 alloy systems [60][61][62] . Therefore, this material might be a promising alternative to these established gate dielectrics in HEMT or other field-effect transistor applications based on Ga2O3, as also recently suggested for the monoclinic modification 63 .…”

Section: Discussionsupporting

confidence: 73%

“…However, there are also reports on band offsets of SiO2 or HfO2 to β-(AlxGa1-x)2O3 thin films, where the valence band offsets are changing much more drastically over a similar composition range of up to 53 at. % aluminum 59,62 . One might therefore be cautious when comparing band offsets in literature even for identical dielectric/semiconductor combinations.…”

Section: Discussionmentioning

confidence: 99%

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Band Offsets at κ-([Al,In]_xGa_1–x)₂O₃/MgO Interfaces

Schultz

Kneiß

Storm

et al. 2020

ACS Appl. Mater. Interfaces

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Conduction and valence band offsets are amongst the most crucial material parameters for semiconductor heterostructure device design, such as for high-electron mobility transistors or quantum-well infrared photodetectors. Due to its expected high spontaneous electrical polarization and the possibility of polarization doping at heterointerfaces similar to the AlGaN/InGaN/GaN system, the metastable orthorhombic κ-phase of Ga2O3 and its indium and aluminum alloy systems are a promising alternative for such device applications. However, respective band offsets to any dielectric are unknown, as well as the evolution of the bands within the alloy systems. We report on valence and conduction band offsets of orthorhombic κ-(AlxGa1-x)2O3 and κ-(InxGa1-x)2O3 thin films to MgO as reference dielectric by X-ray photoelectron spectroscopy. The thin films with compositions xIn ≤ 0.27 and xAl ≤ 0.55 were grown by pulsed laser deposition utilizing tin-doped and radially-segmented targets. The determined band alignments reveal the formation of a type I heterojunction to MgO for all compositions with conduction band offsets of at least 1.4 eV, providing excellent electron confinement. Only low valence band offsets with a maximum of ~300 meV were observed. Nevertheless, this renders MgO as promising gate dielectric for metaloxide-semiconductor transistors in the orthorhombic modification. We further found that the conduction band offsets in the alloy systems are mainly determined by the evolution of the bandgaps, which can be tuned by the composition in a wide range between 4.1 and 6.2 eV, since the energy position of the valence band maximum stays almost constant over the complete composition range investigated. Therefore, tunable conduction band offsets of up to 1.1 eV within the alloy systems allow for subniveau transition energies in (AlxGa1-x)2O3/(InxGa1-x)2O3/(AlxGa1x)2O3 quantum wells from the IR to the visible regime, which are promising for application in quantum-well infrared photodetectors.

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Section: Discussionsupporting

confidence: 73%

Section: Discussionmentioning

confidence: 99%

Band Offsets at κ-([Al,In]_xGa_1–x)₂O₃/MgO Interfaces

Schultz

Kneiß

Storm

et al. 2020

ACS Appl. Mater. Interfaces

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“…A high-resolution X-ray photoelectron spectroscopy (HR-XPS) was implemented to collect the energy core levels (CLs) for each element and photoemission spectra of the individual layer. This technique is widely adopted to investigate the VBOs of two semiconductor materials at the interface including our previous studies [15][16][17][18]. The B 0.14 Al 0.86 N layer of Sample C must be thin enough to allow the CLs spectra from the bottom GaN layer to be detected.…”

Section: Materials Growth and Methodsmentioning

confidence: 99%

Nearly-zero valence band and large conduction band offset at BAlN/GaN heterointerface for optical and power device application

Sun

Park

et al. 2018

Applied Surface Science

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Wurtzite BAlN alloy with large bandgap is an emerging material system for UV optoelectronic and power devices. In this study, the BAlN/GaN heterojunction with a sharp interface and uniform distribution of the elements was formed by careful control of epitaxial conditions to avoid GaN desorption and parasitic reactions whose band alignment was then measured for the first time. The valence band offset (VBO) was found to be nearly-zero, i.e. −0.2 ± 0.2 eV, in the B 0.14 Al 0.86 N/GaN heterojunction by X-ray photoelectron spectroscopy. Additionally, the conduction band offset (CBO) is estimated at 2.1 ± 0.2 eV, which is the largest reported CBO among epitaxial GaN-based heterojunctions. In comparison to the type-I Al 0.75 Ga 0.25 N/GaN heterojunction (both Al 0.75 Ga 0.25 N and B 0.14 Al 0.86 N alloy have the same bandgap of 5.7 eV), the CBO and VBO of the B 0.14 Al 0.86 N/GaN heterostructure are significantly larger and smaller, respectively. The nearly-zero VBO and the very large CBO of the B 0.14 Al 0.86 N/ GaN heterojunction could potentially lead to considerable performance enhancement for GaN optoelectronics and power electronics devices.

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“…The higher oxidation states of Ga reflected in Ga-O bond have been considered as one of the factors that introduce a high interfacial defect density and traps [21], [22]. [21], [24]. The XPS spectra of N 1s core levels is basically not affected by N 2 PDA which may be due to the simultaneous increase of the bonds related to Ga-N and Al-N.…”

Section: Resultsmentioning

confidence: 99%

Impact of Surface Treatments and Post-Deposition Annealing Upon Interfacial Property of ALD-Al₂O₃ on a-Plane GaN

Zhang

et al. 2020

IEEE J. Electron Devices Soc.

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Optimization of interface characteristics between dielectric and non-polar GaN surface is very important and urgent for vertical GaN MOS device whose channel is perpendicular to the conventional c-plane. In this work, the effects of piranha cleaning and N 2 post deposition annealing (PDA) to the interface between atomic-layer-deposited (ALD)-Al 2 O 3 and a-plane GaN samples were comprehensively investigated by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and photo-assisted capacitance-voltage (C-V) measurements. The piranha cleaning and N 2 annealing can improve interface characteristics through the reduction in surface roughness and Ga-O bonds, respectively. Therefore, the frequency dispersion and hysteresis are nearly suppressed with a low interface trap quantity (Q it) of 4.1×10 11 cm-2 and a low average interface state density (D it) of 2.04×10 11 cm-2 •eV-1 from photo-assisted C-V measurements, showing the great promise of utilizing piranha pretreatment, buffered oxide etch (BOE) dip, and N 2 annealing as an effective route to improve the vertical GaN MOS interface properties.

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Band alignment of SiO2/(Al Ga1-)2O3 (0 ≤x≤ 0.49) determined by X-ray photoelectron spectroscopy

Cited by 41 publications

References 25 publications

Band Offsets at κ-([Al,In]_xGa_1–x)₂O₃/MgO Interfaces

Band Offsets at κ-([Al,In]_xGa_1–x)₂O₃/MgO Interfaces

Nearly-zero valence band and large conduction band offset at BAlN/GaN heterointerface for optical and power device application

Impact of Surface Treatments and Post-Deposition Annealing Upon Interfacial Property of ALD-Al₂O₃ on a-Plane GaN

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Band alignment of SiO2/(Al Ga1-)2O3 (0 ≤x≤ 0.49) determined by X-ray photoelectron spectroscopy

Cited by 41 publications

References 25 publications

Band Offsets at κ-([Al,In]xGa1–x)2O3/MgO Interfaces

Band Offsets at κ-([Al,In]xGa1–x)2O3/MgO Interfaces

Nearly-zero valence band and large conduction band offset at BAlN/GaN heterointerface for optical and power device application

Impact of Surface Treatments and Post-Deposition Annealing Upon Interfacial Property of ALD-Al₂O₃ on a-Plane GaN

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Band Offsets at κ-([Al,In]_xGa_1–x)₂O₃/MgO Interfaces

Band Offsets at κ-([Al,In]_xGa_1–x)₂O₃/MgO Interfaces