High quality AlGaN epilayers grown on sapphire using SiN  interlayers

Forghani, Kamran; Klein, Martin; Lipski, Frank; Schwaiger, Stephan; Hertkorn, J.; Leute, Robert A. R.; Scholz, F.; Feneberg, Martin; Neuschl, Benjamin; Thonke, Klaus; Klein, Oliver; Kaiser, Ute; Gutt, Richard; Passow, T.

doi:10.1016/j.jcrysgro.2010.08.044

Cited by 37 publications

(30 citation statements)

References 16 publications

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“…Best result within this series were obtained for a deposition time of 6 min (sample: S3) yielding a HRXRD (102)-reflection with FWHM of 1406". On the other hand, similar to our previous experiences with Al 0.2 Ga 0.8 N [6], the (002) peak width increased with respect to the reference sample. Also here, we observed that the overgrowth of the SiN x nanomask with AlGaN can lead to the formation of AlGaN nanoislands.…”

Section: Sin X Nanomask After 150 Nmsupporting

confidence: 90%

“…It seems that the use of SiN x interlayers for the improvement of AlGaN epilayers is a challenging issue. However, we could realize Al 0.2 Ga 0.8 N epilayers with high crystalline quality (reduced dislocation density) just by a careful optimization of the SiN x nanomask deposition process [6]. Light output power of UV-LEDs grown on those templates showed an increase by a factor of 20 in comparison to the UV-LEDs grown on the templates without SiN x interlayers [6,7,8].…”

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confidence: 99%

“…However, we could realize Al 0.2 Ga 0.8 N epilayers with high crystalline quality (reduced dislocation density) just by a careful optimization of the SiN x nanomask deposition process [6]. Light output power of UV-LEDs grown on those templates showed an increase by a factor of 20 in comparison to the UV-LEDs grown on the templates without SiN x interlayers [6,7,8]. This motivated us to study the applicability of SiN x nanomasks to realize a low number of dislocationsespecially edge-type dislocations -in MOVPE grown AlGaN layers with higher Al-content (30%).…”

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confidence: 99%

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In‐situ deposited SiN_x nanomask for crystal quality improvement in AlGaN

Forghani

Gharavipour

Klein

et al. 2011

Phys. Status Solidi C

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We report the growth of high crystal quality Al0.3Ga0.7N directly on sapphire substrates with metalorganic vapour phase epitaxy. We studied the improvements in crystal quality by introducing an in‐situ deposited SiNx interlayer. It acts as a nanomask which results in termination of the dislocations near the interface between the nanomask and epilayer. The epilayers with no SiNx interlayer have very low density of screw type dislocations evident from transmission electron microscopy (TEM) investigations confirmed by a very narrow X‐ray diffraction symmetric reflection (60”). This is a result of our oxygen doped AlN nucleation layer used to grow such epilayers. On the other hand, such epilayers have very broad XRD asymmetric reflections (typically a few thousand arcsec) indicating a high density of edge type dislocations. We could decrease the latter which are the main existing dislocations in our AlGaN epilayers. In TEM micrographs, we observed the formation of dislocation “bundles” when introducing SiNx interlayers. This phenomenon promotes the dislocation free areas on the surface of the wafer. We carried out accurate optimizations of the SiNx deposition. Consequently, we could grow high quality Al0.3Ga0.7N epilayers with much narrower XRD asymmetric peaks–782” with total sample thickness of 1.4 µm (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Sin X Nanomask After 150 Nmsupporting

confidence: 90%

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confidence: 99%

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confidence: 99%

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In‐situ deposited SiN_x nanomask for crystal quality improvement in AlGaN

Forghani

Gharavipour

Klein

et al. 2011

Phys. Status Solidi C

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“…Most threading dislocations are blocked by the SiNx network, and those emanating from the pores are mostly bent into horizontal configurations. The ELO technique with dielectric masks has also been used for TDD reduction in AlGaN with low Al-molar fraction intended for applications in LEDs in the UVA range [80]. For AlN and high Almolar fraction AlGaN, the slow lateral growth rate of Al containing compounds and the lowselectivity between a mask and unmasked area due to large sticking coefficient of Al adatoms Figure 6.…”

Section: Epitaxial Lateral Overgrowth Of Aln and High Al-molar Fractimentioning

confidence: 99%

Status of Growth of Group III-Nitride Heterostructures for Deep Ultraviolet Light-Emitting Diodes

et al. 2017

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Abstract:We overview recent progress in growth aspects of group III-nitride heterostructures for deep ultraviolet (DUV) light-emitting diodes (LEDs), with particular emphasis on the growth approaches for attaining high-quality AlN and high Al-molar fraction AlGaN. The discussion commences with the introduction of the current status of group III-nitride DUV LEDs and the remaining challenges. This segues into discussion of LED designs enabling high device performance followed by the review of advances in the methods for the growth of bulk single crystal AlN intended as a native substrate together with a discussion of its UV transparency. It should be stated, however, that due to the high-cost of bulk AlN substrates at the time of writing, the growth of DUV LEDs on foreign substrates such as sapphire still dominates the field. On the deposition front, the heteroepitaxial growth approaches incorporate high-temperature metal organic chemical vapor deposition (MOCVD) and pulsed-flow growth, a variant of MOCVD, with the overarching goal of enhancing adatom surface mobility, and thus epitaxial lateral overgrowth which culminates in minimization the effect of lattice-and thermal-mismatches. This is followed by addressing the benefits of pseudomorphic growth of strained high Al-molar fraction AlGaN on AlN. Finally, methods utilized to enhance both p-and n-type conductivity of high Al-molar fraction AlGaN are reviewed.

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“…[76] For AlN and high Al-molar fraction AlGaN, the slow lateral growth rate of Al containing compounds and the low-selectivity between a mask and unmasked area due to large sticking coefficient of Al adatoms precludes the possibility of using dielectric masks for ELO. Maskless ELO by laterally overgrowing a trench instead of a mask material is an alternative avenue to reduce densities of both threading dislocations and cracks.…”

Section: Epitaxial Lateral Overgrowth Of Aln and High Al-molar Fractimentioning

confidence: 99%

Status of Growth of Group III-Nitride Heterostructures for Deep Ultraviolet Light-Emitting Diodes

Ding¹,

Avrutin²,

Özgür³

et al. 2017

Preprint

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Abstract:We overview recent progress in growth aspects of group III-nitride heterostructures for deep ultraviolet (DUV) light-emitting diodes (LEDs), with particular emphasis on the growth approaches for attaining high-quality AlN and high Al-molar fraction AlGaN. The discussion commences with the introduction of the current status of group III-nitride DUV LEDs and the remaining challenges. This segues into discussion of LED designs enabling high device performance followed by the review of advances in the methods for the growth of bulk single crystal AlN intended as a native substrate together with a discussion of its UV transparency. It should be stated, however, that due to the high-cost of bulk AlN substrates at the time of this writing, the growth of DUV LEDs on foreign substrates such as sapphire still dominates the field. On the deposition front, the heteroepitaxial growth approaches incorporate high-temperature metal organic chemical vapor deposition (MOCVD) and pulsed-flow growth, a variant of MOCVD, with the overarching goal of enhancing adatom surface mobility, and thus epitaxial lateral overgrowth which culminates in minimization the effect of lattice-and thermal-mismatches. This is followed by addressing the benefits of pseudomorphic growth of strained high Al-molar fraction AlGaN on AlN. Finally, methods utilized to enhance both p-and n-type conductivity of high Al-molar fraction AlGaN are reviewed.

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High quality AlGaN epilayers grown on sapphire using SiN interlayers

Cited by 37 publications

References 16 publications

In‐situ deposited SiN_x nanomask for crystal quality improvement in AlGaN

In‐situ deposited SiN_x nanomask for crystal quality improvement in AlGaN

Status of Growth of Group III-Nitride Heterostructures for Deep Ultraviolet Light-Emitting Diodes

Status of Growth of Group III-Nitride Heterostructures for Deep Ultraviolet Light-Emitting Diodes

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High quality AlGaN epilayers grown on sapphire using SiN interlayers

Cited by 37 publications

References 16 publications

In‐situ deposited SiNx nanomask for crystal quality improvement in AlGaN

In‐situ deposited SiNx nanomask for crystal quality improvement in AlGaN

Status of Growth of Group III-Nitride Heterostructures for Deep Ultraviolet Light-Emitting Diodes

Status of Growth of Group III-Nitride Heterostructures for Deep Ultraviolet Light-Emitting Diodes

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In‐situ deposited SiN_x nanomask for crystal quality improvement in AlGaN

In‐situ deposited SiN_x nanomask for crystal quality improvement in AlGaN