Contact Engineering of III-Nitrides and Metal Schemes toward Efficient Deep-Ultraviolet Light-Emitting Diodes

Zhao, Xiaoyu; Sun, Ke; Lv, Zhenxing; Liao, Zhefu; Liu, Sheng; Zhou, Shengjun

doi:10.1021/acsami.3c15303

Cited by 3 publications

(1 citation statement)

References 57 publications

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“…Aluminum nitride (AlN) is a wide-band-gap material used in versatile applications such as ultraviolet optoelectronic devices, high-frequency high-power electronics, piezoelectric microelectromechanical systems, and acoustic-wave resonators. − To achieve good crystalline quality and hence a better device performance, AlN is usually grown on c -plane sapphire or 6H-SiC (0001) substrates to ensure a compatibility of crystal symmetry and lattice constant between the two materials. However, problems associated with these substrates are high cost, limited wafer size, and incompatibility with Si-industry processes.…”

Section: Introductionmentioning

confidence: 99%

Crack-Free AlN Film Grown on Sputtered-AlN/2D MoS₂ Seed Layers on a Si(100)-Based Wafer: Implications for Radio-Frequency Acoustic Filters

Hyot,

Dussaigne,

Patouillard

et al. 2024

ACS Appl. Nano Mater.

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Aluminum nitride (AlN)-based acoustic filters are key devices of radio-frequency communications. However, the performance of electroacoustic resonators remains limited by the crystalline quality of the piezoelectric AlN material. An innovative material strategy that combines different types of materials (2D and 3D materials) and growth techniques is presented here to enhance the crystalline quality of thick AlN films grown on silicon-based substrates. Building upon previous works showing the efficacy of 2D MoS 2 in sputtered-AlN texturing, this paper demonstrates how an in situ thermochemical treatment of the sputtered-AlN/MoS 2 seed layers succeeded by a metal organic vapor phase epitaxy (MOVPE) AlN regrowth significantly enhances the crystalline quality of the AlN layer and avoids the detrimental stack delamination at the weak AlN/MoS 2 interface. This paper shows that a delicate balance in the thickness of the sputtered-AlN film should be found to facilitate species diffusion toward the underlying MoS 2 without compromising its texturizing properties for the subsequent MOVPE AlN regrowth. The sputtered-AlN/MoS 2 seed layers involve a nanometric AlN film of less than 5 nm deposited onto three monolayers of MoS 2 . The heat treatment induces an unexpected chemical and structural nanometric reorganization at the interface, converting the initial lamellar MoS 2 film into a discontinuous covalently bonded MoN x O y film, followed by the appearance of metallic Mo nanoparticles at an elevated temperature. Subsequent MOVPE AlN regrowth on the annealed seed layer stacks enables the growth of thick AlN films of up to 600 nm with a mosaicity of less than 0.3°without delamination or cracks. This approach not only facilitates the integration of thick AlN films on Si-based wafers but also opens avenues for growing III−N or other 3D materials on Si through the intercalation of 2D materials. KEYWORDS: highly oriented ALD MoS 2 , highly oriented AlN, sputtered AlN, MOVPE AlN growth, van der Waals interface, NH 3 heat treatments, RF acoustic filter

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Section: Introductionmentioning

confidence: 99%

Crack-Free AlN Film Grown on Sputtered-AlN/2D MoS₂ Seed Layers on a Si(100)-Based Wafer: Implications for Radio-Frequency Acoustic Filters

Hyot,

Dussaigne,

Patouillard

et al. 2024

ACS Appl. Nano Mater.

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Efficiency boosting of 236 nm AlGaN-based micro-LEDs

Li,

Lu,

Zhu

et al. 2024

J. Phys. D: Appl. Phys.

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In this study, 236 nm AlGaN-based deep ultraviolet (DUV) Micro-LEDs with different sized P-contact areas are designed and fabricated, and the sidewall is restored by wet chemical treatment method with KOH solution. The results reveal that proper KOH treatment could effectively remove plasma damaged materials and clearly show the formation of m-plane facets. Compared with untreated Micro-LEDs, the reverse leakage current of the treated Micro-LEDs under -10 V decreases by up to 91.7% and the specific contact resistivity reduces from 6.94 Ωcm2 to 0.07 Ωcm2. The underlying mechanism is that KOH treatment removes the sidewall defects which leads to surface nonradiative recombination sites and surface leakage. Moreover, KOH treatment also removes contaminations on the P+-GaN surface and leads to lower specific contact resistivity. However, too long treatment also destructs the 20 nm P+-GaN layer, which results in higher voltage but less DUV light absorption. As a result, peak light output power density increases from 2.12 W/cm2 to 4.01 W/cm2, representing an 89.2% increase. The efficiency enhancement of Micro-LEDs is anticipated to facilitate the development of DUV Micro-LEDs in maskless lithography and high-capacity DUV non-line of sight communication.

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Significant improvement of n-contact performance and wall plug efficiency of AlGaN-based deep ultraviolet light-emitting diodes by atomic layer etching

Liu,

Cao

et al. 2024

Opt. Lett.

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The reactive ion etching (RIE) process is needed to fabricate deep ultraviolet (DUV) light-emitting diodes (LEDs). However, the n-contact performance deteriorates when the high-Al n-AlGaN surface undergoes RIE, leading to decreased LED performance. In this study, we employed an atomic layer etching (ALE) technology to eliminate surface damage generated during the mesa etching process, thus enhancing the n-Al0.65Ga0.35N ohmic contact. The improved contact performance reduced LED operation voltage and mitigated device heat generation. It was observed that DUV LEDs treated with 200 cycles of ALE showed a reduction in operating voltage from 8.3 to 5.2 V at 10 mA, with a knee voltage of 4.95 V. The peak wall plug efficiency (WPE) was approximately 1.74 times that of reference devices. The x-ray photoelectron spectroscopy (XPS) analysis revealed that ALE removed the surface damage layer induced by plasma etching, eliminating surface nitrogen vacancies and increasing surface electron concentration. Consequently, it facilitated better ohmic contact formation on n-Al0.65Ga0.35N. This study demonstrates that the ALE technology achieves etching with minor surface damage and is suitable for use in III-nitride materials and devices to remove surface defects and contaminations, leading to improved device performance.

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Contact Engineering of III-Nitrides and Metal Schemes toward Efficient Deep-Ultraviolet Light-Emitting Diodes

Cited by 3 publications

References 57 publications

Crack-Free AlN Film Grown on Sputtered-AlN/2D MoS₂ Seed Layers on a Si(100)-Based Wafer: Implications for Radio-Frequency Acoustic Filters

Crack-Free AlN Film Grown on Sputtered-AlN/2D MoS₂ Seed Layers on a Si(100)-Based Wafer: Implications for Radio-Frequency Acoustic Filters

Efficiency boosting of 236 nm AlGaN-based micro-LEDs

Significant improvement of n-contact performance and wall plug efficiency of AlGaN-based deep ultraviolet light-emitting diodes by atomic layer etching

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Contact Engineering of III-Nitrides and Metal Schemes toward Efficient Deep-Ultraviolet Light-Emitting Diodes

Cited by 3 publications

References 57 publications

Crack-Free AlN Film Grown on Sputtered-AlN/2D MoS2 Seed Layers on a Si(100)-Based Wafer: Implications for Radio-Frequency Acoustic Filters

Crack-Free AlN Film Grown on Sputtered-AlN/2D MoS2 Seed Layers on a Si(100)-Based Wafer: Implications for Radio-Frequency Acoustic Filters

Efficiency boosting of 236 nm AlGaN-based micro-LEDs

Significant improvement of n-contact performance and wall plug efficiency of AlGaN-based deep ultraviolet light-emitting diodes by atomic layer etching

Contact Info

Product

Resources

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Crack-Free AlN Film Grown on Sputtered-AlN/2D MoS₂ Seed Layers on a Si(100)-Based Wafer: Implications for Radio-Frequency Acoustic Filters

Crack-Free AlN Film Grown on Sputtered-AlN/2D MoS₂ Seed Layers on a Si(100)-Based Wafer: Implications for Radio-Frequency Acoustic Filters