Channel mobility evaluation for diamond MOSFETs using gate-to-channel capacitance measurement

Hirama, Kazuyuki; Takayanagi, H.; Yamauchi, S.; Yang, Junghoon; Umezawa, Hamao; Kawarada, Hiroshi

doi:10.1016/j.diamond.2008.02.031

Cited by 8 publications

(3 citation statements)

References 14 publications

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“…It was observed that there was a hysteresis and the flat band difference was about 0.5 V [17], which may be attributed to the interface states at the H-diamond/Al2O3 interface. By integrating the C-V curve, the hole density at each gate voltage can be obtained [18,19]. Based on the extracted Rch of the channel under the gate and the 2DHG density ps, the 2DHG mobility μch under the channel can be calculated, as the formulas and results shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

2.1 W/mm Output Power Density at 10 GHz for H-Terminated Diamond MOSFETs With (111)-Oriented Surface

Qiao,

Dai,

et al. 2024

IEEE J. Electron Devices Soc.

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This paper presents high performance hydrogen-terminated diamond MOSFETs fabricated on a (111)-oriented single-crystal diamond substrate. The diamond surface was passivated by a high-quality Al2O3 grown by ALD at 350°C as well as a secondary passivation layer Si3N4 deposited by PECVD. After passivation, a low ohmic contact resistance Rc of 0.5 Ω•mm was obtained and the 2DHG sheet density was as high as 1.0×10 13 cm -2 with a corresponding mobility of 104 cm 2 /V•s. The fabricated diamond MOSFET with gate length of 0.5 μm showcased a high current density of 750 mA/mm, a low on-resistance of 24 Ω•mm, and a high off-state breakdown voltage of 117 V. Thanks to the high current density and low on-resistance, a record high output power density of 2.1 W/mm was achieved at 10 GHz with drain biased at a low voltage of -30 V. These results demonstrate that the output current and output power can be improved by using a (111)-oriented diamond, which is benefit for high-frequency and high-power RF devices.

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Section: Resultsmentioning

confidence: 99%

2.1 W/mm Output Power Density at 10 GHz for H-Terminated Diamond MOSFETs With (111)-Oriented Surface

Qiao,

Dai,

et al. 2024

IEEE J. Electron Devices Soc.

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“…Although some breakthroughs have been realized, the performances of the H-diamond transistors are still far from expected [4][5][6][7][8][9]. One of the most important reasons is that the large surface resistance caused by its low 2DHG mobility has limited their performances [10]. In addition, the H-diamond transistors, especially those fabricated by using a self-aligned process, always suffer from instabilities for lack of effective passivation Manuscript…”

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confidence: 99%

1 W/mm Output Power Density for H-Terminated Diamond MOSFETs With Al₂O₃/SiO₂Bi-Layer Passivation at 2 GHz

Zhou

et al. 2021

IEEE J. Electron Devices Soc.

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We have demonstrated a novel method of depositing ALD-Al2O3/PECVD-SiO2 bi-layer dielectric to passive the surface channels of the hydrogen-terminated diamond (H-diamond). After Al2O3/SiO2 passivation, the surface current increased with time and then tended to be saturated. Afterwards, it became much more stable and showed a larger current than an unpassivated counterpart. The H-diamond MOSFETs were fabricated by using this bi-layer passivation structure and an extremely low Ohmic contact resistance of 0.87 Ω•mm was obtained. The H-diamond RF MOSFET with gate length of 0.45 μm achieved a high current density of -549 mA/mm and an extrinsic fT/fmax of 15/36 GHz. By load-pull measurement, a high output power density of 1.04 W/mm was obtained at frequency of 2 GHz. The results reveal that it is a promising solution for high-stable and high-power diamond transistors by using the Al2O3/SiO2 bi-layer passivation. Index Terms-H-diamond, bi-layer passivation, output power. I. INTRODUCTIONINCE the first hydrogen-terminated diamond (H-diamond) transistor was born in 1994, the H-diamond has attracted more and more attentions to develop high performance RF transistors for its remarkable properties such as high concentration of two dimensional hole gas (2DHG), large critical breakdown electric field of 10 MV/cm, as well as high thermal conductivity of 22 W•cm -1 •K -1 [1-3]. Although some breakthroughs have been realized, the performances of the H-diamond transistors are still far from expected [4][5][6][7][8][9]. One of the most important reasons is that the large surface resistance caused by its low 2DHG mobility has limited their performances [10]. In addition, the H-diamond transistors, especially those fabricated by using a self-aligned process, always suffer from instabilities for lack of effective passivation Manuscript

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“…An understanding of the conduction mechanism would enable us to increase the surface conductivity and improve the performance of devices such as high power, high frequency field-effect transistors (FETs). 10,11) It has been observed that the surface conductivity decreases in vacuum, while it recovers after subsequent exposure to air. 12) Air is composed of many gases, but it appears that its main components (such as N 2 and O 2 ) do not influence the surface resistance.…”

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Improvement of Hydrogen-Terminated Diamond Field Effect Transistors in Nitrogen Dioxide Atmosphere

Kubovič

Kasu

2009

Appl. Phys. Express

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The electrical properties of field effect transistors (FETs) fabricated on hydrogen-terminated diamond have been greatly improved by exposing the diamond surface to nitrogen dioxide. Exposure to NO2 gas significantly increased the hole sheet charge density up to 1.3×1014 cm-2, which is several times higher than previously reported values. FETs exposed to NO2 gas exhibited lower source and drain resistances, which facilitated a 1.8 fold increase in maximum drain current, transconductance increased 1.5 times and power gain cut-off frequency increased 1.6 times.

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Channel mobility evaluation for diamond MOSFETs using gate-to-channel capacitance measurement

Cited by 8 publications

References 14 publications

2.1 W/mm Output Power Density at 10 GHz for H-Terminated Diamond MOSFETs With (111)-Oriented Surface

2.1 W/mm Output Power Density at 10 GHz for H-Terminated Diamond MOSFETs With (111)-Oriented Surface

1 W/mm Output Power Density for H-Terminated Diamond MOSFETs With Al₂O₃/SiO₂Bi-Layer Passivation at 2 GHz

Improvement of Hydrogen-Terminated Diamond Field Effect Transistors in Nitrogen Dioxide Atmosphere

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Channel mobility evaluation for diamond MOSFETs using gate-to-channel capacitance measurement

Cited by 8 publications

References 14 publications

2.1 W/mm Output Power Density at 10 GHz for H-Terminated Diamond MOSFETs With (111)-Oriented Surface

2.1 W/mm Output Power Density at 10 GHz for H-Terminated Diamond MOSFETs With (111)-Oriented Surface

1 W/mm Output Power Density for H-Terminated Diamond MOSFETs With Al2O3/SiO2Bi-Layer Passivation at 2 GHz

Improvement of Hydrogen-Terminated Diamond Field Effect Transistors in Nitrogen Dioxide Atmosphere

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1 W/mm Output Power Density for H-Terminated Diamond MOSFETs With Al₂O₃/SiO₂Bi-Layer Passivation at 2 GHz