Influence of In on the surface morphology of HVPE grown GaN

Dam, C.E.C.; Hageman, P.R.; Enckevort, W.J.P. van; Bohnen, T.; Larsen, P.K.

doi:10.1016/j.jcrysgro.2007.06.005

Cited by 6 publications

(7 citation statements)

References 22 publications

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“…All these results clearly showed that a GaN epitaxial layer with a device-quality smooth as-grown surface and a good thickness uniformity, comparable to that produced by the MOCVD method, can be obtained by the HVPE method, contrary to the beliefs regarding HVPE growth that are commonly held among the GaN material community. [30][31][32][33][34] HVPE growth on freestanding GaN substrates produced surfaces of a similar quality. As examples, a DIC surface image and an AFM image of unintentionally doped GaN layers grown by the HVPE method are shown in Figs.…”

Section: Resultsmentioning

confidence: 85%

“…However, only a few attempts have been made to apply this technique, probably because of widely held beliefs regarding the drawbacks of the HVPE method, such as the high background donor concentrations (resulting from residual Si and O, instead of C) 17,23) and difficulties in producing smooth as-grown surfaces [30][31][32] and uniform thickness, as required for device structures. 33,34) Even for high-crystalline-quality GaN crystals grown by HVPE, residual donor concentrations from 10 15 to 10 17 cm −3…”

Section: Introductionmentioning

confidence: 99%

“…35,36) Roughening of GaN surfaces by pits and hillocks is often observed in HVPE-grown materials. [30][31][32] Difficulties in achieving a uniform thickness by HVPE growth have been also reported. 33,34) However, these problems have not previously been regarded as serious, because the aim of earlier HVPE studies was to fabricate freestanding single crystals of GaN whose surface roughness and thickness nonuniformity could be removed by a subsequent polishing process.…”

Section: Introductionmentioning

confidence: 99%

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Hydride-vapor-phase epitaxial growth of highly pure GaN layers with smooth as-grown surfaces on freestanding GaN substrates

Fujikura

Konno

Yoshida

et al. 2017

Jpn. J. Appl. Phys.

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Thick (20–30 µm) layers of highly pure GaN with device-quality smooth as-grown surfaces were prepared on freestanding GaN substrates by using our advanced hydride-vapor-phase epitaxy (HVPE) system. Removal of quartz parts from the HVPE system markedly reduced concentrations of residual impurities to below the limits of detection by secondary-ion mass spectrometry. Appropriate gas-flow management in the HVPE system realized device-quality, smooth, as-grown surfaces with an excellent uniformity of thickness. The undoped GaN layer showed insulating properties. By Si doping, the electron concentration could be controlled over a wide range, down to 2 × 1014 cm−3, with a maximum mobility of 1150 cm2·V−1·s−1. The concentration of residual deep levels in lightly Si-doped layers was in the 1014 cm−3 range or less throughout the entire 2-in. wafer surface. These achievements clearly demonstrate the potential of HVPE as a tool for epitaxial growth of power-device structures.

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Section: Resultsmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hydride-vapor-phase epitaxial growth of highly pure GaN layers with smooth as-grown surfaces on freestanding GaN substrates

Fujikura

Konno

Yoshida

et al. 2017

Jpn. J. Appl. Phys.

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“…The deep trenches in Fig. 5b suggest a locally decreased mobility of the steps on the expanding sidefaces [23].…”

Section: Contributedmentioning

confidence: 96%

The nucleation of HCl and Cl₂‐based HVPE GaN on mis‐oriented sapphire substrates

Bohnen

Dreumel

Weyher

et al. 2010

Phys. Status Solidi (c)

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The nucleation of both classic HCl‐based and novel Cl 2 ‐ based HVPE GaN on mis‐oriented sapphire substrates was investigated. The use of Cl2in HVPE increases the growth rate by a factor of 4‐5 and strongly reduces the parasitic deposition, allowing for the growth of much thicker wafers than HCl‐based HVPE. Morphological SEM surface studies of the HCl‐based HVPE sample surface show that at 600 °C a nanocrystalline layer is deposited on the sapphire. During the subsequent annealing phase, the morphology changes to a μm‐sized island structure. During overgrowth at 1080 °C, the islands coalesce. Small voids or pinholes are then formed in between the coalescing GaN islands. These pinholes lead to numerous pits on the surface of the GaN at thicknesses of 5 μm. The pits disappear during continued overgrowth and can no longer be found on the surface, when the GaN film reaches a thickness of 45 μm. This particular coalescence mechanism also applies to Cl2‐based HVPE GaN on sapphire (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…The pinned spots expand slower than the rest of the step, resulting in the dark lines trailing from the islands' edges to the location of the defect, as schematically shown in Fig. 11 [25]. Alternatively, these fjörd-like lines might be the result of grain boundaries, which were not overgrown or etched during the annealing phase.…”

Section: On the Nucleation And Coalescence Of CL 2 -Based Hvpe Gan Onmentioning

confidence: 99%

Enhanced growth rates and reduced parasitic deposition by the substitution of Cl2 for HCl in GaN HVPE

Bohnen

Ashraf

Dreumel

et al. 2010

Journal of Crystal Growth

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Influence of In on the surface morphology of HVPE grown GaN

Cited by 6 publications

References 22 publications

Hydride-vapor-phase epitaxial growth of highly pure GaN layers with smooth as-grown surfaces on freestanding GaN substrates

Hydride-vapor-phase epitaxial growth of highly pure GaN layers with smooth as-grown surfaces on freestanding GaN substrates

The nucleation of HCl and Cl₂‐based HVPE GaN on mis‐oriented sapphire substrates

Enhanced growth rates and reduced parasitic deposition by the substitution of Cl2 for HCl in GaN HVPE

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Influence of In on the surface morphology of HVPE grown GaN

Cited by 6 publications

References 22 publications

Hydride-vapor-phase epitaxial growth of highly pure GaN layers with smooth as-grown surfaces on freestanding GaN substrates

Hydride-vapor-phase epitaxial growth of highly pure GaN layers with smooth as-grown surfaces on freestanding GaN substrates

The nucleation of HCl and Cl2‐based HVPE GaN on mis‐oriented sapphire substrates

Enhanced growth rates and reduced parasitic deposition by the substitution of Cl2 for HCl in GaN HVPE

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The nucleation of HCl and Cl₂‐based HVPE GaN on mis‐oriented sapphire substrates