Separation of laterally overgrown GaN template by using selective electrochemical etching

Jeon, Dae Woo; Cho, Han Su; Park, Jae-Woo; Jang, Lee Woon; Kim, Myoung; Jeon, Junhyub; Ju, Jin Woo; Baek, Jong Hyeob; Lee, In Hwan

doi:10.1016/j.jallcom.2012.07.016

Cited by 12 publications

(3 citation statements)

References 24 publications

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“…Several approaches have been proposed to improve the crystal quality, such as epitaxial lateral overgrowth (ELOG), pendeo-epitaxy (PE), and patterned sapphire substrate (PSS). − ELOG has successfully achieved high-quality epitaxial growth with a dislocation density as low as 10 7 –10 6 cm –2 in the wing area by the dislocation filtering effect of the mask. However, dislocations in the window area propagate upward without being blocked, leading to high dislocation density regions that limit the device’s valid range. − In our previous work, we used serpentine channel patterned mask sapphire substrates (SCPSS) to decrease the dislocation density (TDD) in both wing and window areas by performing a modulated ELOG process. − …”

Section: Introductionmentioning

confidence: 99%

Enhanced Performance of InGaN Light-Emitting Diodes via High-Quality GaN and Embedded Air Voids Grown on Hexagonal 3D Serpentine Mask Sapphire Substrates

Chen,

Lei,

Meng

et al. 2023

ACS Photonics

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This work demonstrates high-efficiency InGaN-based light-emitting diodes (HSM-LEDs) prepared on hexagonal 3D serpentine sapphire substrates. The 3D serpentine mask has a modulating effect on epitaxial lateral growth (ELOG), which can not only reduce the dislocation density (TDD) to 1.7 × 107 cm–2 without any high dislocation density (HDD) region but also induce the formation of a hexagonal pyramidal air-void array with an inclination angle of 65°. Compared to conventional LEDs, HSM-LEDs exhibit a 117% enhancement in EL output power at a current injection of 600 mA. This can be attributed to the improvement of crystal quality by modulated ELOG, the relief of in-plane stresses to mitigate the quantum-confined Stark effect (QCSE) through the weak connection of the epitaxial layer to the substrate, and the enhanced light extraction efficiency by an embedded air-void array. We confirmed the reduction of compressive stress from 0.94 GPa to 0.51 GPa in HSM-LEDs by Raman spectroscopy and investigated the effect of air voids on light extraction efficiency (LEE) experimentally and theoretically. Ray-tracing simulations show that the embedded pyramidal air voids can effectively re-extract the downward emitted light, and the pyramidal air voids with a 65° slant sidewall can improve the LEE by 71%.

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Section: Introductionmentioning

confidence: 99%

Enhanced Performance of InGaN Light-Emitting Diodes via High-Quality GaN and Embedded Air Voids Grown on Hexagonal 3D Serpentine Mask Sapphire Substrates

Chen,

Lei,

Meng

et al. 2023

ACS Photonics

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“…To further enhance the performance of optoelectronic devices, patterned sapphire substrates (PSSs) are widely used to strengthen the light extraction efficiency (LEE) and external quantum efficiency [ 4 , 5 , 6 ]. The utilization of PSSs could greatly annihilate dislocations [ 4 , 7 , 8 , 9 ]. Interestingly, with the appropriate nucleation layer (NL), most GaN grows in the flat regions between cones, though the flat region is a rather small proportion of the whole substrate, no matter what the geometry of the pattern is [ 10 , 11 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

Comparative Research of GaN Growth Mechanisms on Patterned Sapphire Substrates with Sputtered AlON Nucleation Layers

Gao

Peng

et al. 2020

Materials

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The utilization of sputtered AlN nucleation layers (NLs) and patterned sapphire substrates (PSSs) could greatly improve GaN crystal quality. However, the growth mechanism of GaN on PSSs with sputtered AlN NLs has not been thoroughly understood. In this paper, we deposited AlON by sputtering AlN with O2, and we found that the variation of thickness of sputtered AlON NLs greatly influenced GaN growth on PSSs. (1) For 10 nm thin AlON sputtering, no AlON was detected on the cone sidewalls. Still, GaN nucleated preferably in non-(0001) orientation on these sidewalls. (2) If the thickness of the sputtered AlON NL was 25 nm, AlON formed on the cone sidewalls and flat regions, and some small GaN crystals formed near the bottom of the cones. (3) If the sputtered AlON was 40 nm, the migration ability of Ga atoms would be enhanced, and GaN nucleated at the top of the cones, which have more chances to grow and generate more dislocations. Finally, the GaN growth mechanisms on PSSs with sputtered AlON NLs of different thicknesses were proposed.

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“…11 Electrochemical (EC) etching is well-known as a selective etching and wide-area etching process for highly n-doped GaN layer. 12 EC etching can be used for such CLO processes, which rely on producing a nanoporous structure by EC etching with subsequent regrowth. 13,14 In this study, we focused on the surface morphology of etched FS-GaN on Ga-and N-polar faces by using EC etching methods.…”

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confidence: 99%

Control of Bowing in Freestanding-GaN Substrate Using Electrochemical Etching Methods

Son¹,

Hwang²,

Jeon³

2018

J. Electrochem. Soc.

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Separation of laterally overgrown GaN template by using selective electrochemical etching

Cited by 12 publications

References 24 publications

Enhanced Performance of InGaN Light-Emitting Diodes via High-Quality GaN and Embedded Air Voids Grown on Hexagonal 3D Serpentine Mask Sapphire Substrates

Enhanced Performance of InGaN Light-Emitting Diodes via High-Quality GaN and Embedded Air Voids Grown on Hexagonal 3D Serpentine Mask Sapphire Substrates

Comparative Research of GaN Growth Mechanisms on Patterned Sapphire Substrates with Sputtered AlON Nucleation Layers

Control of Bowing in Freestanding-GaN Substrate Using Electrochemical Etching Methods

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