Defect Reduction in AlN Epilayers Grown by MOCVD via Intermediate-Temperature Interlayers

Chen, Sheng‐Chang; Yang, Li; Ding, Yawen; Li, Senlin; Zhang, Min; Wu, Zhihao; Fang, Yanyan; Dai, Jiangnan; Chen, Chang

doi:10.1007/s11664-014-3462-1

Cited by 20 publications

(15 citation statements)

References 17 publications

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“…3(a) , it is clear that the dislocations bend laterally in the region around the PF-AlN layer, and merge with other dislocations, forming half loops and thus curbing the upward spreading. Similar results were reported by other groups 8 , 9 . The effectiveness of PF-AlN is also viewed in Fig.…”

Section: Resultssupporting

confidence: 93%

“…Since the growth temperature below 1000 °C favors 3D island formation, the LT-AlN was employed to produce the nucleation centers for subsequent crystal coalescence 10 . The Mid-AlN was adopted to alleviate lattice strain and to bend the dislocations as the enlarged AlN islands coalesced at the increased temperature 8 , 9 . The temperature is further increased to 1180 °C for the high-temperature AlN (HT-AlN) to promote lateral diffusion length 16 .…”

Section: Resultsmentioning

confidence: 99%

“…Moreover, in order to alleviate the huge lattice strain between AlN and the sapphire substrate, it is often indispensable to insert low-temperature (LT, < 1000 °C) buffer layers under the high-temperature AlN 8 – 10 . Because of the difficulty in rapid and precise control over the RF-heater (or heating filament), changing the substrate temperature can be a very time-consuming process, particularly for the buffer growth involving periodic temperature oscillation to mitigate the undesired strain 8 , 9 . The high temperature and long growth time of AlN are among the keys reasons for the pricey ultraviolet light emitting diodes.…”

Section: Introductionmentioning

confidence: 99%

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High-quality AlN grown with a single substrate temperature below 1200 °C

Huang

Gupta

Wang

et al. 2017

Sci Rep

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1.5-μm AlN grown by metal-organic chemical vapor deposition (MOCVD), with a single substrate temperature of 1180 °C, exhibits atomically flat surface and the XRD (102) peak width of 427 arcsec. The results are achieved with a pulsed NH3-flow condition, serving as an alternative for the commonly used temperature-varied buffer structure, which is often complicated and time-consuming. Inserting two pulsed-NH3-flow AlN layers in the epitaxial structure not only releases the lattice strain via the formation of three-dimensional nano-islands, but also smoothens the surface with prolonged lateral migration of Al adatoms. This effective growth technique substantially simplifies the manufacture of device-quality AlN.

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Section: Resultssupporting

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High-quality AlN grown with a single substrate temperature below 1200 °C

Huang

Gupta

Wang

et al. 2017

Sci Rep

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“…Thus, the AlN epilayer is nearly stress-free. [17,36,40,42,43,46,53,56,[58][59][60]62,69,73,74,76,79,81,94,[98][99][100][101][102][103][104][105][106][107][108][109] It is noted that there has been no unified standard for the evaluation of TDD. X-ray rocking curve (XRC) scan is the most common method to evaluate TDD.…”

Section: Quasi-van Der Waals Epitaxy (Qvdwe)mentioning

confidence: 99%

“…Figure 23. Selected AlN/sapphire TDD by year of publication[17,36,40,42,43,46,53,56,[58][59][60]62,69,73,74,76,79,81,94,[98][99][100][101][102][103][104][105][106][107][108][109]. The ultralow TDD value of 3.4 × 10 7 cm −2 has been achieved by ELOG growth technique in 2006.…”

mentioning

confidence: 99%

Recent Advances in Fabricating Wurtzite AlN Film on (0001)-Plane Sapphire Substrate

Zhang

et al. 2021

Crystals

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Ultrawide bandgap (UWBG) semiconductor materials, with bandgaps far wider than the 3.4 eV of GaN, have attracted great attention recently. As a typical representative, wurtzite aluminum nitride (AlN) material has many advantages including high electron mobility, high breakdown voltage, high piezoelectric coefficient, high thermal conductivity, high hardness, high corrosion resistance, high chemical and thermal stability, high bulk acoustic wave velocity, prominent second-order optical nonlinearity, as well as excellent UV transparency. Therefore, it has wide application prospects in next-generation power electronic devices, energy-harvesting devices, acoustic devices, optical frequency comb, light-emitting diodes, photodetectors, and laser diodes. Due to the lack of low-cost, large-size, and high-ultraviolet-transparency native AlN substrate, however, heteroepitaxial AlN film grown on sapphire substrate is usually adopted to fabricate various devices. To realize high-performance AlN-based devices, we must first know how to obtain high-crystalline-quality and controllable AlN/sapphire templates. This review systematically summarizes the recent advances in fabricating wurtzite AlN film on (0001)-plane sapphire substrate. First, we discuss the control principles of AlN polarity, which greatly affects the surface morphology and crystalline quality of AlN, as well as the electronic and optoelectronic properties of AlN-based devices. Then, we introduce how to control threading dislocations and strain. The physical thoughts of some inspirational growth techniques are discussed in detail, and the threading dislocation density (TDD) values of AlN/sapphire grown by various growth techniques are compiled. We also introduce how to achieve high thermal conductivities in AlN films, which are comparable with those in bulk AlN. Finally, we summarize the future challenge of AlN films acting as templates and semiconductors. Due to the fast development of growth techniques and equipment, as well as the superior material properties, AlN will have wider industrial applications in the future.

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Unambiguously Enhanced Ultraviolet Luminescence of AlGaN Wavy Quantum Well Structures Grown on Large Misoriented Sapphire Substrate

Sun

Mitra

Subedi

et al. 2019

Adv Funct Materials

143

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High‐quality epitaxy consisting of Al1−xGaxN/Al1−yGayN multiple quantum wells (MQWs) with sharp interfaces and emitting at ≈280 nm is successfully grown on sapphire with a misorientation angle as large as 4°. Wavy MQWs are observed due to step bunching formed at the step edges. A thicker QW width accompanied by a greater accumulation of gallium near the macrostep edge than that on the flat‐terrace is observed on 4° misoriented sapphire, leading to the generation of potential minima with respect to their neighboring QWs. Consequently, a significantly enhanced photoluminescence intensity (at least ten times higher), improved internal quantum efficiency (six times higher at low excitation laser power), and a much longer carrier lifetime are achieved. Importantly, the wafer‐level output‐power of the ultraviolet light emitting diodes on 4° misoriented substrate is nearly increased by 2–3 times. This gain is attributed to the introduction of compositional inhomogeneities in AlGaN alloys induced by gallium accumulation at the step‐bunched region thus forming a lateral potential well for carrier localization. The experimental results are further confirmed by a numerical modeling in which a 3D carrier confinement mechanism is proposed. Herein, the compositional modulation in active region arising from the substrate misorientation provides a promising approach in the pursuit of high‐efficient ultraviolet emitters.

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Defect Reduction in AlN Epilayers Grown by MOCVD via Intermediate-Temperature Interlayers

Cited by 20 publications

References 17 publications

High-quality AlN grown with a single substrate temperature below 1200 °C

High-quality AlN grown with a single substrate temperature below 1200 °C

Recent Advances in Fabricating Wurtzite AlN Film on (0001)-Plane Sapphire Substrate

Unambiguously Enhanced Ultraviolet Luminescence of AlGaN Wavy Quantum Well Structures Grown on Large Misoriented Sapphire Substrate

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