Analysis of HVPE grown AlGaN layers on honeycomb patterned sapphire

Fleischmann, Simon; Mogilatenko, A.; Hagedorn, Sylvia; Richter, E.; Goran, Daniel; Schäfer, P.; Zeimer, U.; Weyers, M.; Tränkle, G.

doi:10.1016/j.jcrysgro.2014.10.010

Cited by 7 publications

(17 citation statements)

References 15 publications

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“…As published in previous works , c ‐plane AlGaN growth on sapphire n ‐plane facets hinders overgrowth of honeycomb‐shaped PSS. In Fig.…”

Section: Resultssupporting

confidence: 52%

“…b). Compared to crystallite growth on honeycomb‐shaped PSS as published in , AlGaN growth on sapphire n ‐facets is strongly suppressed. This can be explained considering a trench‐like feature at the basis of the columns (Fig.…”

Section: Resultsmentioning

confidence: 74%

“…SEM top‐view micrograph of AlGaN growth on honeycomb‐shaped PSS (a), model of occurrence of stable sapphire micro facets inside PSS (b) and scheme of stable sapphire facets (c). Sapphire n ‐facets acting as origin of AlGaN crystallites hindering overgrowth are highlighted in yellow. Black arrows indicate propagation of crystallites.…”

Section: Resultsmentioning

confidence: 99%

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Triangular-shaped sapphire patterning for HVPE grown AlGaN layers

Fleischmann

Richter

Mogilatenko

et al. 2016

Phys. Status Solidi A

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AlGaN growth by hydride vapor phase epitaxy on patterned sapphire substrates has been investigated. Growth on honeycomb-shaped holes is disturbed by parasitic growth of c-plane oriented AlGaN crystallites on n-plane sapphire facets. Triangular hole-like structures allow for complete suppression of parasitic c-plane oriented AlGaN crystallites and coalescence of c-plane AlGaN at very low layer thickness. Additionally, triangular columnar sapphire patterns allow for biaxial strain relaxation and higher crystalline perfection. A total pressure of 400 hPa is favored for lateral overgrowth of ternary AlGaN by hydride vapor phase epitaxy. Lower pressures lead to strong composition inhomogeneity and higher pressure to lower crystal perfection. Additionally, very low V/III ratios of less than 10 yield best results. Lower ammonia supply support the growth of beneficial {11-22}-AlGaN crystallites on sapphire m-sidewalls which supresses undesired AlGaN growth on sapphire n-facets.

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“…As published in previous works , c ‐plane AlGaN growth on sapphire n ‐plane facets hinders overgrowth of honeycomb‐shaped PSS. In Fig.…”

Section: Resultssupporting

confidence: 52%

Section: Resultsmentioning

confidence: 74%

See 1 more Smart Citation

Triangular-shaped sapphire patterning for HVPE grown AlGaN layers

Fleischmann

Richter

Mogilatenko

et al. 2016

Phys. Status Solidi A

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“…An AlGaN layer grown on top of a buffer layer deposited at a very low V/III ratio of 1 shows differently oriented crystallites on the surface as well as comparably high XRD FWHM in the skew‐symmetric 30–32 reflection. Our previous studies showed that AlGaN growth on honeycomb‐patterned sapphire can lead to enhanced growth of differently oriented crystallites originating from the sidewalls. The crystallites originating from the PSS sidewalls showed a high symmetry as well as ordering in the same spatial pattern as the substrate.…”

Section: Resultsmentioning

confidence: 99%

“…The pattern and its fabrication are described in Refs. . The AlN buffer was grown with the same parameters varied: relative ratio between group V and group III precursors and temperature.…”

Section: Influence Of Aln Buffer Morphology and Crystal Quality On Sumentioning

confidence: 99%

Influence of AlN buffer layer on growth of AlGaN by HVPE

Fleischmann

Richter

Mogilatenko

et al. 2017

Physica Status Solidi (b)

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To the end of improvement of layer morphology and crystalline perfection of thick AlGaN layers grown by hydride vapor phase epitaxy (HVPE) as well as for the suppression of crystallite formation during growth, the impact of AlN buffer layer properties on AlGaN growth was investigated. While the surface morphology of 500 nm thick AlN layer improves with higher V/III ratio toward 50 and lower growth temperatures of 1020 °C, its use as a buffer layer for thick AlGaN layers leads to strong degradation of AlGaN surface and even to formation of different crystallites during growth. Best surface morphology and crystalline perfection of thick AlGaN layers was observed for the growth on an AlN buffer layer with a higher crystal quality disregarding its 3D morphology and high surface roughness. Best results were achieved at medium V/III ratio of about 10–20 and AlN buffer growth temperature of 1060 °C.

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