Effects of Interfacial Thin Metal Layer for High-Performance Pt–Au-Based Schottky Contacts to AlGaN–GaN

Miura, Naruhisa; Oishi, Toshiyuki; Nanjo, Takuma; Suita, Muneyoshi; Abe, Yuji; Ozeki, Tatsuo; Ishikawa, Hiroyasu; Egawa, Takashi

doi:10.1109/ted.2003.822472

Cited by 31 publications

(24 citation statements)

References 20 publications

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“…All the contacts exhibit higher capacitance value at low frequency. This capacitance increase at low measurement frequency was reported to be attributed to the interface defect density [3]. For the Ni/Rh/Au contact, the frequency dependence of the capacitance becomes smaller after annealing, indicating reduced defects at the metal/GaN interface, and leads to improved SBH.…”

Section: Methodsmentioning

confidence: 88%

“…For the Ni/Rh/Au contact, the frequency dependence of the capacitance becomes smaller after annealing, indicating reduced defects at the metal/GaN interface, and leads to improved SBH. Possibly Ni acts to reduce the defects by chemical reaction [3]. However, in the case of the Rh/Au contact, the capacitance dependence on the measurement frequency hardly changes after annealing.…”

Section: Methodsmentioning

confidence: 99%

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Rhodium‐based Schottky contacts on n‐doped gallium nitride

Tian¹,

Chor

2008

Phys. Status Solidi (c)

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Electrical characteristics and thermal stability of Rhodium (Rh)‐based Schottky contacts on n‐GaN, including Rh/Au and Ni/Rh/Au, have been investigated and compared with those of the Ni/Au contact. Although the maximum Schottky barrier height (SBH) of the Rh/Au contact is slightly lower than that of Ni/Au, the inclusion of a thin Ni layer to yield the Ni/Rh/Au contact has led to a maximum SBH of 0.80 eV, surpassing that of Ni/Au by 0.07 eV and leading to a reduced reverse leakage current at ‐1 V by 1 order of magnitude com‐ pared to that of Ni/Au. The good performance of the Ni/Rh/Au contact can be attributed to the co‐existence of Rh and a thin layer of Ni, which leads to limited adverse reaction of Ni with the GaN substrate, and formation of NiO and reduced interfacial defects at the metal/GaN interface. In addition, thermal stability studies have shown that Rh‐based contacts exhibit better morphological stability than Ni/Au, and the Ni/Rh/Au contact has improved thermal stability over Rh/Au and Ni/Au contacts. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Methodsmentioning

confidence: 88%

Section: Methodsmentioning

confidence: 99%

Rhodium‐based Schottky contacts on n‐doped gallium nitride

Tian¹,

Chor

2008

Phys. Status Solidi (c)

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“…The AlGaN used for this particular study had a 35 % Al content. Multilayer metal systems have been investigated on AlGaN/GaN based semiconductors [5][6][7]. In particular these studies have been done on Ni/Au metal schemes by inserting different metals between the Ni and Au in order to lower the reverse leakage current [8].…”

Section: Introductionmentioning

confidence: 99%

Optical and electrical characterization of AlGaN based Schottky photodiodes after annealing at different temperatures

Ngoepe

Meyer

Diale

et al. 2014

Physica B: Condensed Matter

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“…8,9 Effects on device performance have been investigated for various techniques used to engineer electrically active surface states-surface passivation, dielectric layer insertion, surface treatments with chemicals or plasma, and post-gate-annealing. [1][2][3][4][5][12][13][14][15][16][17][18] We have reported that thermal annealing after Schottky gate formation can be used to engineer surface/interface states in AlGaN/GaN HEMTs to improve device RF power performance; it has been suggested this is related to the change of trap activities near the metal/AlGaN interface. 5 Reported annealing effects on Schottky contacts on AlGaN/GaN heterostructures include reduction of reverse leakage current and improvement of Schottky barrier height and breakdown voltage.…”

Section: Introductionmentioning

confidence: 99%

Passivation of Surface and Interface States in AlGaN/GaN HEMT Structures by Annealing

Kim

Schuette

Lee

et al. 2007

Journal of Elec Materi

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The Ni/AlGaN interfaces in AlGaN/GaN Schottky diodes were investigated to explore the physical origin of post-annealing effects using electron beam induced current (EBIC), current-voltage (I-V) characteristics, and X-ray photoelectron spectroscopy (XPS). The EBIC images of the annealed diodes showed that the post-annealing process reduces electrically active states at the Schottky metal/AlGaN interfaces, leading to improvement of diode performance, for example a decrease in reverse leakage current and an increase in Schottky barrier heights. Pulsed I-V characteristics indicate the Fermi level is up-shifted after annealing, resulting in a larger sheet carrier density at the AlGaN/GaN interface. Unintentional oxidation of the free AlGaN surface during the post-annealing process, revealed by XPS analysis, may prevent electron trapping near the drain-side of the gate edges. We suggest that the post-annealing process under an optimized conditions can be an effective way of passivating AlGaN/GaN heterojunction field-effect transistors.

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Effects of Interfacial Thin Metal Layer for High-Performance Pt–Au-Based Schottky Contacts to AlGaN–GaN

Cited by 31 publications

References 20 publications

Rhodium‐based Schottky contacts on n‐doped gallium nitride

Rhodium‐based Schottky contacts on n‐doped gallium nitride

Optical and electrical characterization of AlGaN based Schottky photodiodes after annealing at different temperatures

Passivation of Surface and Interface States in AlGaN/GaN HEMT Structures by Annealing

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