Growth of GaN boules via vertical HVPE

Richter, E.; Gründer, M.; Netzel, Carsten; Weyers, M.; Tränkle, G.

doi:10.1016/j.jcrysgro.2011.12.030

Cited by 17 publications

(9 citation statements)

References 21 publications

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“…Besides generation of threading dislocations, one of the most frequently encountered problems in the GaN HVPE growth is related to the formation of V-shaped defects or pits on the surface which may reach millimeter dimensions in thick layers. 9 In spite of the fact that intentionally produced pits can be used as dislocation sink for the purpose of reducing the density of threading dislocations, 10 the occurrence of V-shaped defects or pits leads, as a rule, to the formation of extended inhomogeneities. [11][12][13][14][15] Attempts to achieve crystal homogeneity by complete overgrowth of the pits during the HVPE process have failed.…”

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confidence: 99%

Self-Organized Three-Dimensional Nanostructured Architectures in Bulk GaN Generated by Spatial Modulation of Doping

Tiginyanu

Stevens‐Kalceff

Sarua

et al. 2016

ECS J. Solid State Sci. Technol.

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Self-organized 3D nanostructured architectures including quasi-ordered concentric hexagonal structures generated during the growth of single crystalline n-GaN substrates by hydride vapor phase epitaxy (HVPE) are reported. The study of as-grown samples by using Kelvin Probe Force Microscopy shows that the formation of self-organized architectures can be attributed to fine modulation of doping related to the spatial distribution of impurities. The specific features of nanostructured architectures involved have been brought to light by using electrochemical and photoelectrochemical etching techniques which are highly sensitive to local doping. The analysis of the results shows that the formation of self-organized spatial architectures in the process of HVPE is caused by the generation of V-pits and their subsequent overgrowth accompanied by the growth in variable direction. It is demonstrated for the first time that the electrical and luminescence properties of HVPE-grown GaN are spatially modulated throughout, including islands between overgrown V-pit regions. The dependence of doping upon growth direction is confirmed by the micro-cathodoluminescence characterization of HVPE-grown pencil-like microcrystals exposing various crystallographic planes along the tip. These results are indicative of new possibilities for defect engineering in gallium nitride and for three-dimensional spatial nanostructuring of this important electronic material by controlling the growth direction. Gallium Nitride (GaN), a wide-bandgap semiconductor compound (E g = 3.4 eV at 300 K), is considered nowadays the second most important semiconductor material after Si. Over the past decades it has played a major role in the development of modern solid-state lighting industry.1-3 An intensive investigation of this compound started in 1970's, but with minimal success in the development of real applications. In the absence of native bulk material, GaN epilayers were grown on foreign substrates and, as a result of the large lattice mismatch and difference in thermal expansion coefficients, the overgrown films contained a high concentration of threading dislocations. The fascinating point, however, is that even in the presence of very high concentrations of dislocations, sometimes exceeding 10 10 cm −2 , gallium nitride exhibits intense luminescence, a property that makes the compound unique in comparison with other III-V materials, such as GaAs, GaP and InP. This particular feature along with other material characteristics were of paramount importance for the development and subsequent commercialization of GaN-based blue light emitting diodes by the mid-1990s. 4 This significant optoelectronic success resulted in the Nobel Prize for Physics being awarded to Shuji Nakamura, Isamu Akasaki and Hiroshi Amano, in 2014. There is no doubt that lighting technologies based on GaN and related nitrides will continue their impactful evolution, particularly in view of the recent demonstration of electrically pumped inversionless polariton lasing at room temper...

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confidence: 99%

Self-Organized Three-Dimensional Nanostructured Architectures in Bulk GaN Generated by Spatial Modulation of Doping

Tiginyanu

Stevens‐Kalceff

Sarua

et al. 2016

ECS J. Solid State Sci. Technol.

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“…diameter without cracks, while inverse pyramidal defects (V‐pits) are still present with enlarged diameter compared to the 1 mm layers. It is suspected that these V‐pits originate from sapphire substrate .…”

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confidence: 99%

Effect of carrier gas in hydride vapor phase epitaxy on optical and structural properties of GaN

Gridneva

Richter

Feneberg

et al. 2015

Physica Status Solidi (b)

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Variation of the H 2 fraction in the carrier gas affects partial pressures and homogeneity of the species at the growth front. Changing the H 2 :N 2 ratio thus requires readjustment of the flows of the reacting species to keep the V/III ratio at the growth front constant. In this paper the complex effect of the carrier gas composition, i.e., the H 2 þ N 2 mixture on optical and structural properties of GaN films grown by hydride vapor phase epitaxy (HVPE) is studied. With constant input flows of the main reactants but different H 2 fractions in each experiment, good morphology was observed only in a small parameter window. Partial pressures at the growth front were calculated using a commercial virtual reactor simulation tool. After readjustment of the growth species partial pressures to those which previously provided good morphology, it became possible to achieve higher growth rates, comparable morphologies, and widths of the rocking curves (FWHM) for a wide range of hydrogen fractions (0-70%). Further flow pattern correction enabled growth of 1 mm thick layers for 40-75% H 2 in the carrier gas. The results of the study allow to find optimal conditions for HVPE growth of thick GaN layers when scaling up from 2 to 3 in. substrate diameter.

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“…1,2 Even though HVPE-grown GaN layers with smooth surfaces have been achieved, 3,4 the formation of V-shaped pits (so-called V-pits) on the surfaces on these GaN layers under extreme conditions is a significant problem. 5,6 The formation of V-pits is often associated with the presence of inversion domains (IDs). [7][8][9][10][11][12] In this case, the appearance of V-pits is believed to result from the difference in the growth rates for different polarities.…”

Section: Introductionmentioning

confidence: 99%

V-shaped pits in HVPE-grown GaN associated with columnar inversion domains originating from foreign particles of α-Si3N4 and graphitic carbon

Matsubara

Denpo

Okada

et al. 2017

Micron

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The v-shaped pits (so-called V-pits) observed in hydride-vapor-phase-epitaxy-grown GaN and associated with the columnar inversion domains originating from foreign particles were investigated. The inversion domains on the front and back surfaces of the test sample were recognized after chemical mechanical polishing. It was found that the V-pits originate from the columnar inversion domains. The inversion domains, in turn, arise from the particles that exist on a low-temperature GaN buffer layer on sapphire substrate. Using transmission electron microscopy, these particles were found to be of α-SiN and graphitic carbon. Such particles are attributable to the components of the reactor and adhere to the low-temperature GaN buffer layer, which has a surface roughness of the order of several nanometers. Thus, an effective way of obtaining HVPE-grown thick GaN layers without the V-pits associated with columnar IDs is to maintain the parts of the HVPE chamber properly to prevent foreign particles from being generated.

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Growth of GaN boules via vertical HVPE

Cited by 17 publications

References 21 publications

Self-Organized Three-Dimensional Nanostructured Architectures in Bulk GaN Generated by Spatial Modulation of Doping

Self-Organized Three-Dimensional Nanostructured Architectures in Bulk GaN Generated by Spatial Modulation of Doping

Effect of carrier gas in hydride vapor phase epitaxy on optical and structural properties of GaN

V-shaped pits in HVPE-grown GaN associated with columnar inversion domains originating from foreign particles of α-Si3N4 and graphitic carbon

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