Capacitively coupled radio frequency nitrogen plasma etch damage to N-type gallium nitride

Kawakami, Retsuo; Takeichi, Atsushi; Niibe, Masahito; Konishi, Masashi; Mori, Yukari; Kotaka, Takuya; Inaoka, Takeshi; Tominaga, Kikuo; Mukai, Takashi

doi:10.1016/j.vacuum.2012.07.006

Cited by 9 publications

(17 citation statements)

References 16 publications

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“…The surface roughening is remarkable in the sample treated for 200 min, and the defect is pit-like. In contrast, the surface morphology did not change for the samples etched with a lower V DC of −200 V (not shown here) [8].…”

Section: Methodsmentioning

confidence: 75%

“…The O 1s XPS spectrum was obtained by the same apparatus. A particle collision model simulation named "PIS", developed by the authors [8], was employed to calculate the composition change of the etched surface.…”

Section: Methodsmentioning

confidence: 99%

“…The Ar plasma generated at a high gas pressure of 50-100 mTorr caused a morphological change (surface roughening and defect formation) in the surfaces as the etching time increased more than sixty minutes [7]. However, in the samples etched by N 2 plasma with a lower self-bias voltage of −200 V, the surface morphologies changed little, and their surfaces were equivalent to that of the asgrown sample [8]. We have further investigated and found that in the samples etched with a higher self-bias voltage of −400 V, the surface morphology changed, roughening with higher gas pressures (50-100 mTorr) and longer treatment times (60-200 min).…”

Section: Introductionmentioning

confidence: 99%

“…We have investigated the damage of n-GaN crystals etched by various plasmas (Ar, He, and N 2 ) using a capacitively coupled radio frequency (RF) plasma reactor [7][8][9]. The Ar plasma generated at a high gas pressure of 50-100 mTorr caused a morphological change (surface roughening and defect formation) in the surfaces as the etching time increased more than sixty minutes [7].…”

Section: Introductionmentioning

confidence: 99%

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Damage Characteristics of n-GaN Crystal Etched with N2 Plasma by Soft X-Ray Absorption Spectroscopy

Niibe

Kotaka

Kawakami

et al. 2016

e-J. Surf. Sci. Nanotech.

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n-GaN crystals were plasma-etched with N2 gas, and their surfaces were analyzed mainly by X-ray photoelectron spectroscopy (XPS) and soft X-ray absorption spectroscopy (XAS). In the samples etched with a high self-bias voltage of −400 V, the surface morphology changed, roughening under the treatment conditions of higher gas pressures (∼100 mTorr) and longer treatment times (∼200 min). In these samples with a roughened surface, the N/Ga composition ratios measured by XPS deviated greatly in the Ga-rich direction from the normal Npreferentially etched sample. Moreover, N-K near-edge X-ray absorption fine structure (NEXAFS) spectra changed greatly from that normally observed in GaN crystals. New peak features were also observed in the O 1s XPS and the O-K NEXAFS spectra. The surface roughening, the composition deviation, and the anomalous spectra in XPS and the NEXAFS correlated well with each other, which indicated the formation of another compound in the surface-roughened sample.

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Section: Methodsmentioning

confidence: 75%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Damage Characteristics of n-GaN Crystal Etched with N2 Plasma by Soft X-Ray Absorption Spectroscopy

Niibe

Kotaka

Kawakami

et al. 2016

e-J. Surf. Sci. Nanotech.

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“…Using a capacitively-coupled radio frequency (RF) plasma reactor, the authors so far have studied damage characteristics of n-GaN surfaces etched by Ar and N 2 plasmas generated with a low applied voltage of V RF = 200 V [8,9]. Here, V RF is the maximum RF voltage.…”

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confidence: 99%

Damage characteristics of n‐GaN thin film surfaces etched by N₂ plasmas

Kawakami¹,

Niibe²,

Nakano³

et al. 2013

Phys. Status Solidi C

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Damage characteristics of n‐GaN surfaces etched by capacitively‐coupled radio frequency N2 plasma, generated with a high applied voltage of 400 V, was studied in terms of synergistic effect between ion bombardment and ultraviolet (UV) light irradiation. The result was compared with that obtained with a low applied voltage of 200 V. Morphology of the surface etched at a low gas pressure of 10 mTorr is similar to that of the as‐grown surface even with increasing etching time, whereas N/Ga ratio at the surface decreases. The result can be explained in terms of the physical etching, though the surface is irradiated with the UV light emitted from the plasma. The result obtained at the low gas pressure is independent of the applied voltage. In contrast, the characteristic at the surface etched at a high gas pressure of 50‐100 mTorr depends on the applied voltage. A morphological change in the surface etched with the high applied voltage occurs, whereas the N/Ga ratio increases The increase in the N/Ga ratio is not reproduced by the simulation, which implies the contribution of the UV light irradiation. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Characteristics of N₂ and O₂ Plasma‐Induced Damages on AlGaN Thin Film Surfaces

Kawakami

Niibe

Nakano

et al. 2017

Physica Status Solidi (a)

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A fundamental understanding of N 2 and O 2 plasma-induced damage on AlGaN surface is needed in order not to severely degrade electrical characteristics and in order to intelligently achieve the normally-off operation of AlGaN/GaN-based electronic devices. A difference between the damage characteristics of Al 0.24 Ga 0.76 N thin film surfaces irradiated with N 2 and O 2 plasmas is reported, from the perspective of impact of ultraviolet (UV) photons emitted from the plasmas. With the lengthening irradiation time, N 2 plasma irradiation introduced a large degree of nitrogen deficiency under the influence of near-UV photons with energies of 3.68 and 3.93 eV larger than the AlGaN band-gap energy, compared to O 2 plasma irradiation without the emission of near-UV photons. In a short irradiation time, O 2 plasma irradiation introduced a larger degree of nitrogen deficiency. With increasing gas pressure, O 2 plasma-induced damage on the surface was more enhanced than N 2 plasma-induced damage. The degree of aluminum deficiency was more enhanced than that of gallium deficiency, the amount of oxides incorporated into the surface was suppressed, and the etch-pit density comparable to the dislocation density was introduced on the surface. These findings can be attributed to the impacts of vacuum ultraviolet photons and energetic O þ ions from the O 2 plasma.

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Capacitively coupled radio frequency nitrogen plasma etch damage to N-type gallium nitride

Cited by 9 publications

References 16 publications

Damage Characteristics of <i>n</i>-GaN Crystal Etched with N<sub>2 </sub>Plasma by Soft X-Ray Absorption Spectroscopy

Damage Characteristics of <i>n</i>-GaN Crystal Etched with N<sub>2 </sub>Plasma by Soft X-Ray Absorption Spectroscopy

Damage characteristics of n‐GaN thin film surfaces etched by N₂ plasmas

Characteristics of N₂ and O₂ Plasma‐Induced Damages on AlGaN Thin Film Surfaces

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Capacitively coupled radio frequency nitrogen plasma etch damage to N-type gallium nitride

Cited by 9 publications

References 16 publications

Damage Characteristics of <i>n</i>-GaN Crystal Etched with N<sub>2 </sub>Plasma by Soft X-Ray Absorption Spectroscopy

Damage Characteristics of <i>n</i>-GaN Crystal Etched with N<sub>2 </sub>Plasma by Soft X-Ray Absorption Spectroscopy

Damage characteristics of n‐GaN thin film surfaces etched by N2 plasmas

Characteristics of N2 and O2 Plasma‐Induced Damages on AlGaN Thin Film Surfaces

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Product

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Damage characteristics of n‐GaN thin film surfaces etched by N₂ plasmas

Characteristics of N₂ and O₂ Plasma‐Induced Damages on AlGaN Thin Film Surfaces