Evidence of reduced interface states in Al<sub>2</sub>O<sub>3</sub>/AlGaN MIS structures via insertion of ex situ regrown AlGaN layer

Baratov, Ali; Kawabata, Shinsaku; Urano, S.; Nagase, I.; Ishiguro, M.; Maeda, S.; Igarashi, T.; Nezu, T.; Yatabe, Zenji; Matys, Maciej; Kachi, Tetsu; Adamowicz, B.; Wakejima, Akio; Kuzuhara, Masaaki; Yamamoto, Akio; Asubar, Joel T.

doi:10.35848/1882-0786/ac8f13

Cited by 5 publications

(2 citation statements)

References 38 publications

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“…In addition, the V-based MIS-HEMT showed a subthreshold swing (SS) value, which is computed from the inverse of the slope of up-swept semi-log transfer curves, of only 80 mV dec −1 in comparison to 90 mV dec −1 of the Ti-based MIS-HEMT. Furthermore, considering the difference between the up-sweep and down-sweep V TH , which is simply called hysteresis (ΔV HYS ), V-based MIS-HEMT is only about 0.65 V, much lower than that of the Tibased device, which is 1.8 V. At this stage, we would like to highlight the key findings of negative shift of V TH , 20) lower value of SS, 21) smaller ΔV HYS , 22) other hand, the V-based device [see Fig. 5(a)], for the two highest V GS (+4 and +2 V), I D can still be sufficiently modulated by V GS .…”

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confidence: 96%

Low thermal budget V/Al/Mo/Au ohmic contacts for improved performance of AlGaN/GaN MIS-HEMTs

Baratov,

Igarashi,

Ishiguro

et al. 2023

Jpn. J. Appl. Phys.

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We report on highly improved performance of Al2O3/AlGaN/GaN MIS-HEMTs using V/Al/Mo/Au metal stack as ohmic electrodes. Transfer length method (TLM) test structures using V/Al/Mo/Au metal stack annealed at temperature of 660 °C revealed highly linear current-voltage curves and smooth surface morphology. Compared with reference MIS-HEMTs using Ti/Al/Mo/Au annealed at standard RTA temperature of 880 °C, V-based devices exhibited less hysteresis of transfer curves and showed higher gate controllability of drain current, suggesting highly improved Al2O3/AlGaN interface. Measurements and analyses of capacitance-voltage characteristics of corresponding MIS-capacitors corroborated these findings. V-based ohmic contact could open new avenues towards enhanced GaN-based MIS-HEMTs performance.

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confidence: 96%

Low thermal budget V/Al/Mo/Au ohmic contacts for improved performance of AlGaN/GaN MIS-HEMTs

Baratov,

Igarashi,

Ishiguro

et al. 2023

Jpn. J. Appl. Phys.

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“…Numerous feasible approaches have been employed, and varying degrees of success have been achieved. For instance, Yamamoto et al and Huang et al used an ex situ regrowth AlGaN insertion layer and an ozone (O 3 ) oxygen source for atomic layer deposition (ALD), respectively, to obtain a high-quality Al 2 O 3 /AlGaN interface. , In addition, the use of wet processing to improve interface quality is also a mainstream method. Joglekar et al and Yoon et al used tetramethylammonium hydroxide (TMAH) to improve the sidewall surface of heterostructures and reduce the surface current of AlGaN/GaN MIS-HEMTs, respectively, both preparing high-performance devices. , While TMAH wet etching is a convenient and simple treatment with relatively few associated variables, there has not been a comprehensive explanation of its influence on insulator/III–nitride interfacial properties.…”

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confidence: 99%

Improved Gate Stability of Metal–Insulator–Semiconductor-High-Electron-Mobility Transistors with 10 nm Atomic Layer Deposition Al₂O₃ by Tetramethylammonium Hydroxide Wet Treatment

Li,

Zhou,

Xing

et al. 2024

ACS Appl. Electron. Mater.

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We investigated the impact of predeposition surface treatment with a tetramethylammonium hydroxide (TMAH) solution on the performance of recessed gate metal−insulator−semiconductorhigh-electron-mobility transistors (MIS-HEMTs). When applying the forward step stress, gate leakage current of the TMAH-treated device becomes 1 order of magnitude smaller. Step stress tests carried out at various voltages showed a stable threshold voltage with both the reverse gate bias step stress and the off-state drain step stress contributing to the high-quality Al 2 O 3 /AlGaN interfaces. When the temperature was increased to 473 K, the maximum field effective mobility (μ FE ) was improved from 450 to 483 cm 2 /V•s, and on-resistance was improved by ∼6.8%.

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Effect of Ultra‐Thin AlGaN Regrown Layer on the Electrical Properties of ZrO₂/AlGaN/GaN Structures

Nezu,

Maeda,

Baratov

et al. 2024

Physica Status Solidi (a)

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Effects of the ultrathin 1 nm thick AlGaN regrown layer before gate insulator deposition on the performance of ZrO2/AlGaN/GaN metal‐insulator‐semiconductor (MIS) structures are investigated. In comparison with the reference ZrO2/AlGaN/GaN MIS high‐electron‐mobility transistors (MIS‐HEMTs), MIS‐HEMTs with AlGaN regrown layer exhibit increased maximum drain current (>1050 mA mm−1) and broader full‐width at half maximum (FWHM) of transconductance profile (11 V). Moreover, the gate leakage current in the forward direction is reduced by about four orders of magnitude while the hysteresis of the transfer curves is cut‐down to more than 40%. Compared with the control MIS‐capacitors (MIS‐caps), MIS‐caps with regrowth show highly evident sudden increase in capacitance known as “spill‐over” in the capacitance–voltage (C–V) profiles, suggesting improved ZrO2/AlGaN interfaces. Extracted electron states from the C–V profiles, reveal 6 times to 14 times reduction of interface states density within 0.2 to 0.8 eV from the AlGaN conduction band edge. Using photo‐assisted C–V measurements, the near mid‐gap electron states density of MIS‐caps is extracted with regrowth to be at least three times less than those of reference MIS‐caps. Findings in this work are very similar to those recently reported Al2O3/regrown‐AlGaN interfaces, suggesting that the regrowth technique could be universal in reducing electron states along insulator/AlGaN interfaces.

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Evidence of reduced interface states in Al₂O₃/AlGaN MIS structures via insertion of ex situ regrown AlGaN layer

Cited by 5 publications

References 38 publications

Low thermal budget V/Al/Mo/Au ohmic contacts for improved performance of AlGaN/GaN MIS-HEMTs

Low thermal budget V/Al/Mo/Au ohmic contacts for improved performance of AlGaN/GaN MIS-HEMTs

Improved Gate Stability of Metal–Insulator–Semiconductor-High-Electron-Mobility Transistors with 10 nm Atomic Layer Deposition Al₂O₃ by Tetramethylammonium Hydroxide Wet Treatment

Effect of Ultra‐Thin AlGaN Regrown Layer on the Electrical Properties of ZrO₂/AlGaN/GaN Structures

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Evidence of reduced interface states in Al2O3/AlGaN MIS structures via insertion of ex situ regrown AlGaN layer

Cited by 5 publications

References 38 publications

Low thermal budget V/Al/Mo/Au ohmic contacts for improved performance of AlGaN/GaN MIS-HEMTs

Low thermal budget V/Al/Mo/Au ohmic contacts for improved performance of AlGaN/GaN MIS-HEMTs

Improved Gate Stability of Metal–Insulator–Semiconductor-High-Electron-Mobility Transistors with 10 nm Atomic Layer Deposition Al2O3 by Tetramethylammonium Hydroxide Wet Treatment

Effect of Ultra‐Thin AlGaN Regrown Layer on the Electrical Properties of ZrO2/AlGaN/GaN Structures

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Evidence of reduced interface states in Al₂O₃/AlGaN MIS structures via insertion of ex situ regrown AlGaN layer

Improved Gate Stability of Metal–Insulator–Semiconductor-High-Electron-Mobility Transistors with 10 nm Atomic Layer Deposition Al₂O₃ by Tetramethylammonium Hydroxide Wet Treatment

Effect of Ultra‐Thin AlGaN Regrown Layer on the Electrical Properties of ZrO₂/AlGaN/GaN Structures