Self‐separation of thick two inch GaN layers grown by HVPE on sapphire using epitaxial lateral overgrowth with masks containing tungsten

Hennig, Ch.; Richter, E.; Weyers, M.; Tränkle, G.

doi:10.1002/pssc.200674855

Cited by 12 publications

(4 citation statements)

References 5 publications

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“…In this work we used dielectric masks, structured by optical lithography and dry etching by an ex situ process. This idea was originally used for defect reduction by epitaxial lateral overgrowth (ELOG) being nowadays fairly well established, and is also applied for self‐separation 6. This method is well reproducible, in particular compared to most of the in situ deposited interlayers.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of freestanding 2″‐GaN wafers by hydride vapour phase epitaxy and self‐separation during cooldown

Lipski

Wunderer

Schwaiger

et al. 2010

Physica Status Solidi (a)

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Using a dielectric mask, structured by optical lithography, freestanding 2 00 -GaN wafers were prepared by hydride vapour phase epitaxy (HVPE) and self-separation during cooldown. The mask was deposited on a GaN template grown on sapphire by metal organic vapour phase epitaxy (MOVPE) and it was shown that the instability of a SiN mask at growth temperature supports the further self-separation. Testing different mask geometries, a hexagonally shaped pattern with a period of 30 mm and an opening of 3 mm showed best performance. This mask allowed the growth and separation of a full 2 00 GaN wafer by utilizing the stress arising during cooldown from thermal mismatch to the substrate. Thickness inhomogenity was below 10% and the samples show good surface morphology.

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Section: Introductionmentioning

confidence: 99%

Fabrication of freestanding 2″‐GaN wafers by hydride vapour phase epitaxy and self‐separation during cooldown

Lipski

Wunderer

Schwaiger

et al. 2010

Physica Status Solidi (a)

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“…Through zone 5, exhaust gas is transported to the exhaust gas treatment system. Various works have been applied on this HVPE reactor [16][17][18][19][20] , and 120 μm thick GaN layer are successfully epitaxy on 2-inch sapphire substrates without cracks [21] .…”

Section: Commercial Hvpementioning

confidence: 99%

Hydride vapor phase epitaxy for gallium nitride substrate

Wei

Yang

et al. 2019

J. Semicond.

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Due to the remarkable growth rate compared to another growth methods for gallium nitride (GaN) growth, hydride vapor phase epitaxy (HVPE) is now the only method for mass product GaN substrates. In this review, commercial HVPE systems and the GaN crystals grown by them are demonstrated. This article also illustrates some innovative attempts to develop homebuilt HVPE systems. Finally, the prospects for the further development of HVPE for GaN crystal growth in the future are also discussed.

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“…7,8) However, freestanding GaN crystals exhibit concave bowing (radius of lattice curvature: R L < 10 m) despite the elimination of sapphire substrates. [9][10][11][12] It was reported that the bowing originates from the lattice mismatch between GaN and sapphire or from the stress generated by the coalescence of islands formed in the nucleation process, but the details in either case are unclear. 13,14) The bowing of the crystal causes non-uniformity in the off-angle over the crystal, resulting in a variation in the epitaxial layer characteristics and a decrease in device performance.…”

Section: Introductionmentioning

confidence: 99%

Influence of GaN/sapphire contact area on bowing of GaN wafer grown by the Na-flux method with a sapphire dissolution process

Yamada¹,

Imanishi²,

Murakami³

et al. 2020

Jpn. J. Appl. Phys.

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Although almost all freestanding GaN crystals exhibit concave bowing despite the elimination of a seed substrate, in the Na-flux multipoint-seed technique, a flat GaN substrate is stably obtained. Unlike other hetero-epitaxial growth techniques, this method allows the GaN/sapphire contact area to be minimized, and this in turn can lead to low curvature. However, the detailed mechanism underlying this effect on curvature is unclear. Therefore, in this study we investigated the relationship between the curvature and the GaN/sapphire contact area of freestanding GaN crystals with the use of a sapphire dissolution technique to eliminate thermal stress. As a result, the radii of the lattice curvatures of the grown crystals increased with a decrease in the contact area, and a GaN substrate with a large diameter (>2 in) and low curvature (>40 m) was obtained. These results may be attributed to grain coalescence on a flat seed.

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Self‐separation of thick two inch GaN layers grown by HVPE on sapphire using epitaxial lateral overgrowth with masks containing tungsten

Cited by 12 publications

References 5 publications

Fabrication of freestanding 2″‐GaN wafers by hydride vapour phase epitaxy and self‐separation during cooldown

Fabrication of freestanding 2″‐GaN wafers by hydride vapour phase epitaxy and self‐separation during cooldown

Hydride vapor phase epitaxy for gallium nitride substrate

Influence of GaN/sapphire contact area on bowing of GaN wafer grown by the Na-flux method with a sapphire dissolution process

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