Stress distribution of GaN layer grown on micro-pillar patterned GaN templates

Nagarajan, S.; Svensk, Olli; Ali, Muhammad; Naresh-Kumar, G.; Trager-Cowan, C.; Suihkonen, Sami; Sopanen, Markku; Lipsanen, Harri

doi:10.1063/1.4813077

Cited by 13 publications

(7 citation statements)

References 24 publications

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“…28 The emergence of E 1 at 532 cm -1 is presumably attributed to the stripe morphology of the SAG-2 nd GaN layer since the E 1 mode of the Raman spectra can be oversusceptible from surface geometry. 30,31 The A 1 (LO) peaks also reflect strain status in a similar manner. The A 1 (LO) peak of the planar 2 nd GaN layer is located at 736 cm -1 without dispersion properties, and this is well matched with the strain-free GaN layer (736.5 ± 0.2 cm -1 ), while the A 1 (LO) peak of the selectively grown GaN layer is at (734.1 cm -1 ), indicating slight tensile strain by the short Raman frequency shift.…”

Section: Optical Properties and Residual Strainmentioning

confidence: 96%

Evolutionary growth of microscale single crystalline GaN on an amorphous layer by the combination of MBE and MOCVD

et al. 2015

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To integrate multiple functional devices on a chip, advances in epitaxial growth on heterosubstances are required. As one approach to achieve an epitaxial layer on an amorphous substrate, we developed a method of combined epitaxial growth using molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD). This two-stage combined growth can be used to grow a binary gallium nitride (GaN) on any thermally durable substances. The first MBE growth step provided us effective nucleation with uniform morphology. Meanwhile, the second MOCVD growth enabled improved crystalline quality. Detailed analysis at grain-to-grain and layer-to-layer interfaces was studied with high-resolution transmission electron microscopy (TEM) characterization. This study gives a deep understanding of the growth behavior, thereby supporting the demonstration of perfect single crystalline GaN, enabling the realization of optoelectronic GaN-based devices on amorphous layer.

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Section: Optical Properties and Residual Strainmentioning

confidence: 96%

Evolutionary growth of microscale single crystalline GaN on an amorphous layer by the combination of MBE and MOCVD

et al. 2015

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“…this misalignment results in the generation of coalescence boundary dislocations required to accommodate the misorientation. The dislocations will thread within the epilayer up to the active region, leading to an inhomogeneous spatial distribution of stress and dislocation density dictated by the geometry of the initial pattern, as has been demonstrated in few studies [10,13].…”

Section: Introductionmentioning

confidence: 89%

Pendeo-epitaxy of GaN on SOI nano-pillars: Freestanding and relaxed GaN platelets on silicon with a reduced dislocation density

Dagher

Mierry

Alloing

et al. 2019

Journal of Crystal Growth

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Nanopendeo-epitaxy of gallium nitride (GaN) is considered in this study as a way of producing freestanding GaN with reduced strain and threading dislocation density (TDD) for optoelectronic applications. The novelty of this work lies in the use of silicon on insulator (SOI) substrates patterned into nano-pillars down to the buried oxide (BOX). We actually want to benefit from the creeping properties of SiO2 at the growth temperature of GaN for strain relaxation and grain-boundary dislocations reduction. In this paper, we report on the fabrication of 40×40 µm 2 and 300×300 µm 2 freestanding GaN platelets, up to 10 µm-thick, spontaneously separated from the initial pillars. Structural and optical characterizations show that the platelets are crack-free and almost fully relaxed, with a TDD of ∼ 4×10 8 /cm 2. We underline the different benefits of this approach, but most importantly, we believe that it will be the founding-brick for transferable GaN-based devices.

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“…There is no direct contact with the exposed sapphire which helps relieve some strain. 37 A minor deterioration of the crystal quality is observed only in the center of window region, which is discerned from the slightly decreased intensity and increased line width of the E 2 (high) phonon as compared to the edge area of window region. This indicates again the improved crystal quality in window region compared with the conventional ELOG.…”

Section: Acs Applied Materials and Interfacesmentioning

confidence: 96%

“…It can be attributed to (i) mixing of the A 1 (LO) with the E 1 (LO) phonon mode due to the crystallographic tilt of ELO layer 32 (ii) LO phonon-plasmon coupling enhanced by the diffusion of Si atoms from the Si 3 N 4 and SiO 2 masks besides n-doped GaN. 25,37 The shoulder peaks of phonon modes at ∼561 cm −1 are observed on both SCPSS and CSS. They should mainly come from the E 2 (high) modes of InGaN layers in MQWs.…”

Section: Acs Applied Materials and Interfacesmentioning

confidence: 99%

Dislocation Reduction and Stress Relaxation of GaN and InGaN Multiple Quantum Wells with Improved Performance via Serpentine Channel Patterned Mask

Zhang

et al. 2016

ACS Appl. Mater. Interfaces

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The existence of high threading dislocation density (TDD) in GaN-based epilayers is a long unsolved problem, which hinders further applications of defect-sensitive GaN-based devices. Multiple-modulation of epitaxial lateral overgrowth (ELOG) is used to achieve high-quality GaN template on a novel serpentine channel patterned sapphire substrate (SCPSS). The dislocation blocking brought by the serpentine channel patterned mask, coupled with repeated dislocation bending, can reduce the dislocation density to a yet-to-be-optimized level of ∼2 × 10(5) to 2 × 10(6) cm(-2). About 80% area utilization rate of GaN with low TDD and stress relaxation is obtained. The periodical variations of dislocation density, optical properties and residual stress in GaN-based epilayers on SCPSS are analyzed. The quantum efficiency of InGaN/GaN multiple quantum wells (MQWs) on it can be increased by 52% compared with the conventional sapphire substrate. The reduced nonradiative recombination centers, the enhanced carrier localization, and the suppressed quantum confined Stark effect, are the main determinants of improved luminous performance in MQWs on SCPSS. This developed ELOG on serpentine shaped mask needs no interruption and regrowth, which can be a promising candidate for the heteroepitaxy of semipolar/nonpolar GaN and GaAs with high quality.

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Stress distribution of GaN layer grown on micro-pillar patterned GaN templates

Cited by 13 publications

References 24 publications

Evolutionary growth of microscale single crystalline GaN on an amorphous layer by the combination of MBE and MOCVD

Evolutionary growth of microscale single crystalline GaN on an amorphous layer by the combination of MBE and MOCVD

Pendeo-epitaxy of GaN on SOI nano-pillars: Freestanding and relaxed GaN platelets on silicon with a reduced dislocation density

Dislocation Reduction and Stress Relaxation of GaN and InGaN Multiple Quantum Wells with Improved Performance via Serpentine Channel Patterned Mask

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