Using a NiZn solid solution layer to produce high-barrier height Schottky contact to semipolar (20–21) n-type GaN

Suk, Jung Hyung; Lee, Tae‐Ju; Seong, Tae Yeon

doi:10.1016/j.jallcom.2020.157003

Cited by 6 publications

(6 citation statements)

References 42 publications

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“…As shown in Figure b, the ideality factor n decreases from 6.5 to 3.1, and the effective SBH increases from 1.12 to 1.79 eV, as the temperature increases from 300 to 450 K. The variation of the ideality factor and barrier height with temperature is a characteristic phenomenon observed in Schottky barriers, possibly stemming from the nonuniformity of the metal–semiconductor interface . The inhomogeneity of barriers in our semipolar AlN may be attributed to threading dislocations caused by the large lattice mismatch between AlN and the substrate, as well as stacking faults and the characteristics of the deposition and surface cleaning procedures …”

Section: Results and Discussionmentioning

confidence: 91%

Semipolar (11–22) AlN Films Grown by Hydride Vapor Phase Epitaxy for Schottky Barrier Diodes

Ji,

Liu,

et al. 2024

Crystal Growth & Design

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High-quality semipolar (11−22) AlN films with a thickness of 8.4 μm are grown on m-plane sapphire by high-temperature hydride vapor phase epitaxy (HVPE). The full widths at half-maximum (FWHMs) of X-ray rocking curves (XRCs) for such films are as small as 641″ and 346″ along [11−23] AlN and [1−100] AlN , respectively. Ohmic contacts with a specific contact resistance of 0.792 Ω•cm 2 are achieved on the unintentionally doped (11−22) AlN films by depositing a Ti/Al/Ni/ Au metal stack, combined with high-temperature rapid annealing at 950 °C. Based on the good crystal quality and ohmic contacts, lateral Schottky barrier diodes (SBDs) are fabricated on the semipolar AlN film. The Ni/Au-AlN SBDs exhibit an ideality factor n of 6.5 and an effective Schottky barrier height (SBH) of 1.12 eV at room temperature. At high temperatures, the ideality factor n falls, while the effective SBH grows, indicating lateral nonuniformities at the metal/semiconductor contact, which can be adequately explained by an inhomogeneous model. Moreover, the large band gap of AlN enables the manufactured SBDs to operate reliably even at a temperature of 450 K.

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Section: Results and Discussionmentioning

confidence: 91%

Semipolar (11–22) AlN Films Grown by Hydride Vapor Phase Epitaxy for Schottky Barrier Diodes

Ji,

Liu,

et al. 2024

Crystal Growth & Design

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“…For p-type GaN materials, it is obvious that the SBH of the p-GaN gate HEMT with SPO is 0.252 eV higher than that of the device without SPO. The increased SBH could be explained according to the metalsemiconductor energy band theory [34][35][36], as shown in the follow formula (5):…”

Section: Resultsmentioning

confidence: 99%

Normally-off GaON/p-GaN gate HEMTs with selective plasma oxidation: from structural characterization, performance improvement to physical mechanism

Wu,

Xing,

Luo

et al. 2024

Semicond. Sci. Technol.

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In this letter, a p-GaN gate high-electron-mobility transistor (HEMT) with a high threshold voltage and better gate reliability was demonstrated by using selective plasma oxidation (SPO) and an additional low-temperature annealing step before gate metal is evaporated. After the SPO, a gallium oxynitride (GaON) dielectric layer was formed on the surface of p-GaN under the gate metal, and was studied by X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), high-resolution transmission electron microscopy (HR-TEM) and energy dispersion spectroscopy (EDS). In addition, the fabricated metal/GaON/p-GaN gate HEMT exhibited a large threshold voltage (VTH) improvement from 1.46 V to 2.47 V. Furthermore, the forward gate breakdown voltage (VGS,BD) increased from 7.55 V to 11.10 V, and the maximum forward gate operating voltage (VGS-max) significantly improved from 5.0 V to 7.80 V for a ten-year lifetime with a 63.2% failure rate. Kelvin Probe Force Microscopy (KPFM) reveals that the surface potential increased after SPO, and the shift of valence band maximum (VBM) obtained by XPS spectra was 0.7 eV lower than that of the p-GaN, which further improves the Schottky barrier height (SBH) at the gate metal/GaON interfaces to holes, thereby improving VTH and reducing IGS of the device. As a barrier layer, GaON suppressed the injection of carrier into the depletion region under a high electric field and enhanced the reliability of the gate.

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“…[34][35][36] Inhomogeneous Schottky barriers are thought to form at the metal-semiconductor (MS) interface owing to uneven doping concentrations, threading dislocations, and locally different metallic phases after thermal annealing. 34,37 Thus, the measured SBHs actually represent the mean values of various SBHs at the MS interface.…”

Section: Resultsmentioning

confidence: 99%

“…These shifts indicate that the surface Fermi levels move toward the valence band edge owing to the generation of acceptor-like Ga vacancies due to Ga out diffusion. 27,37,47 In other words, the Ag-Ga binary phase diagram indicates the high solubility of Ga atoms in Ag (18.7 at%) at approximately 600 °C. 48,49 Thus, Ga atoms are believed to outdiffuse into Ag to form an Ag-Ga solid solution upon annealing.…”

Section: Resultsmentioning

confidence: 99%

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Electrical Characteristics of Thermally Stable Ag–Pd–Cu Alloy Schottky Contacts on n-Al_0.6Ga_0.4N

Sim

Kim

Seong

et al. 2022

ECS J. Solid State Sci. Technol.

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We report the fabrication of high-barrier-height and thermally reliable Schottky contacts to n-Al0.6Ga0.4N by using an Ag-Pd-Cu (APC) alloy. The Schottky barrier heights (SBHs) and ideality factors computed using the current-voltage (I-V) model ranged from 0.82 to 0.97 eV and from 3.15 to 3.44, respectively. The barrier inhomogeneity model and capacitance-voltage (C-V) method yielded higher SBHs (1.62–2.19 eV) than those obtained using the I-V model. The 300 ℃-annealed APC sample exhibited more uniform electrical characteristics than the 500 ℃-annealed Ni/Au Schottky samples (each with the best Schottky behavior). Furthermore, the scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) results indicated that the APC Schottky contacts were more thermally stable than the Ni/Au contacts. On the basis of the X-ray photoemission spectroscopy (XPS) results, the improved Schottky characteristics of the APC alloy contacts are described and discussed.

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Using a NiZn solid solution layer to produce high-barrier height Schottky contact to semipolar (20–21) n-type GaN

Cited by 6 publications

References 42 publications

Semipolar (11–22) AlN Films Grown by Hydride Vapor Phase Epitaxy for Schottky Barrier Diodes

Semipolar (11–22) AlN Films Grown by Hydride Vapor Phase Epitaxy for Schottky Barrier Diodes

Normally-off GaON/p-GaN gate HEMTs with selective plasma oxidation: from structural characterization, performance improvement to physical mechanism

Electrical Characteristics of Thermally Stable Ag–Pd–Cu Alloy Schottky Contacts on n-Al_0.6Ga_0.4N

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Using a NiZn solid solution layer to produce high-barrier height Schottky contact to semipolar (20–21) n-type GaN

Cited by 6 publications

References 42 publications

Semipolar (11–22) AlN Films Grown by Hydride Vapor Phase Epitaxy for Schottky Barrier Diodes

Semipolar (11–22) AlN Films Grown by Hydride Vapor Phase Epitaxy for Schottky Barrier Diodes

Normally-off GaON/p-GaN gate HEMTs with selective plasma oxidation: from structural characterization, performance improvement to physical mechanism

Electrical Characteristics of Thermally Stable Ag–Pd–Cu Alloy Schottky Contacts on n-Al0.6Ga0.4N

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Product

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Electrical Characteristics of Thermally Stable Ag–Pd–Cu Alloy Schottky Contacts on n-Al_0.6Ga_0.4N