The impact of surface states on the DC and RF characteristics of AlGaN/GaN HFETs

Vetury, R.; Zhang, N.Q.; Keller, S.; Mishra, Umesh K.

doi:10.1109/16.906451

Cited by 1,306 publications

(787 citation statements)

References 13 publications

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“…[7][8][9] All of these distinct characteristics are useful for power devices. [10][11][12][13] It has been known that the electron density of the AlGaN/GaN heterostructure increases with the thickness of Al x Ga 1−x N and Al mole fraction x. 14 In an endeavor to integrate the merits of these two material systems, there have recently been substantial studies on current transport from graphene to Al x Ga 1−x N/GaN heterostructure.…”

Section: Introductionmentioning

confidence: 99%

Current transport mechanism in graphene/AlGaN/GaN heterostructures with various Al mole fractions

et al. 2016

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The current transport mechanism of graphene formed on AlxGa1−xN/GaN heterostructures with various Al mole fractions (x = 0.15, 0.20, 0.30, and 0.40) is investigated. The current–voltage measurement from graphene to AlGaN/GaN shows an excellent rectifying property. The extracted Schottky barrier height of the graphene/AlGaN/GaN contacts increases with the Al mole fraction in AlGaN. However, the current transport mechanism deviates from the Schottky-Mott theory owing to the deterioration of AlGaN crystal quality at high Al mole fractions confirmed by reverse leakage current measurement.

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Section: Introductionmentioning

confidence: 99%

Current transport mechanism in graphene/AlGaN/GaN heterostructures with various Al mole fractions

et al. 2016

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“…However, all the fabricated devices had gate length/barrier thickness aspect ratios larger than 5 at least, then no short channel effect was expected to take place. Another responsible mechanism is formation of virtual gates [1][2][3][4] , where the effective gate length is virtually longer than that of geometrical size due to unintentional charging up of the surface at the gate periphery.…”

Section: Characteristics Of Fabricated Hfetsmentioning

confidence: 99%

“…It is also problem that their cut-off frequency is saturated around 100 GHz, even when the gate length is reduced less than 100 nm. Recent researches have revealed that these problems strongly relate to surfaces of GaN-based materials [1][2][3] , however, their mechanisms have not been understood enough yet.…”

Section: Introductionmentioning

confidence: 99%

Gate control, surface leakage currents, and peripheral charging in AlGaN/GaN heterostructure field effect transistors having nanometer-scale schottky gates

Kasai

Kotani

Hashizume

et al. 2006

J. Electron. Mater.

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Gate control properties together with gate leakage currents in AlGaN/GaN HFETs with nm-scale Schottky gates were investigated focusing on effects of AlGaN surfaces at the gate periphery. Fabricated AlGaN/GaN HFETs showed unexpectedly small gate length (L G )-dependence of transconductance, g m . Comparison of transfer characteristics from theory and experiment, effective L G in the fabricated devices were found much longer than geometrical size in the order of 100 nm, indicating the formation of virtual gates. Detailed analysis of the gate leakage current behaviors based on a thin surface barrier model showed the presence of strong electric field at the gate periphery. Mechanism of the virtual gate formation was discussed based on the obtained nm-scale Schottky gate behaviors.

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“…On the other hand, the potential of AlGaN/GaN HEMTs is greatly limited for high-speed and high-power applications by the current collapse effect. This effect is also described as dynamic behavior degradation, gate lag, drain lag, etc., which is caused by the charge trapping effect on the AlGaN surface especially in the access region between gate and drain [4][5][6]. In order to solve these two issues, the deposition of oxide-based dielectric such as SiO 2 [7], Al 2 O 3 [8], LaLuO 3 [9], and SrO 2 [10,11] and dielectric stack such as SiN/Al 2 O 3 [12] as gate dielectric layer and passivation layer in the access region simultaneously is widely adopted.…”

Section: Introductionmentioning

confidence: 99%

AlGaN/GaN MISHEMTs with AlN gate dielectric grown by thermal ALD technique

Liu¹,

Zhao²,

Zhang³

et al. 2016

Nano Online

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Recently, AlN plasma-enhanced atomic layer deposition (ALD) passivation technique had been proposed and investigated for suppressing the dynamic on-resistance degradation behavior of high-electron-mobility transistors (HEMTs). In this paper, a novel gate dielectric and passivation technique for GaN-on-Si AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MISHEMTs) is presented. This technique features the AlN thin film grown by thermal ALD at 400°C without plasma enhancement. A 10.6-nm AlN thin film was grown upon the surface of the HEMT serving as the gate dielectric under the gate electrode and as the passivation layer in the access region at the same time. The MISHEMTs with thermal ALD AlN exhibit enhanced on/off ratio, reduced channel sheet resistance, reduction of gate leakage by three orders of magnitude at a bias of 4 V, reduced threshold voltage hysteresis of 60 mV, and suppressed current collapse degradation.

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The impact of surface states on the DC and RF characteristics of AlGaN/GaN HFETs

Cited by 1,306 publications

References 13 publications

Current transport mechanism in graphene/AlGaN/GaN heterostructures with various Al mole fractions

Current transport mechanism in graphene/AlGaN/GaN heterostructures with various Al mole fractions

Gate control, surface leakage currents, and peripheral charging in AlGaN/GaN heterostructure field effect transistors having nanometer-scale schottky gates

AlGaN/GaN MISHEMTs with AlN gate dielectric grown by thermal ALD technique

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