Electron microscopy analysis of microstructure of postannealed aluminum nitride template

Kaur, Jesbains; Kuwano, Noriyuki; Jamaludin, Khairur Rijal; Mitsuhara, Masatoshi; Saito, Hikaru; Hata, Satoshi; Suzuki, Shuhei; Miyake, Hideto; Hiramatsu, Kazumasa; Fukuyama, Hidetoshi

doi:10.7567/apex.9.065502

Cited by 10 publications

(3 citation statements)

References 33 publications

(31 reference statements)

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“…According to the Al 2 O 3 -AlN-AlON system phase diagram [26] , the γ-AlON does not directly contribute to the crystalline optimization. However, as we know, the as-sputtered AlN film exhibits columnar-like AlN grains which perform lateral polarity distribution and the grain boundaries between these domains are important source of threading dislocations [28,29] . As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Four-inch high quality crack-free AlN layer grown on a high-temperature annealed AlN template by MOCVD

et al. 2021

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In this work, based on physical vapor deposition and high-temperature annealing (HTA), the 4-inch crack-free high-quality AlN template is initialized. Benefiting from the crystal recrystallization during the HTA process, the FWHMs of X-ray rocking curves for (002) and (102) planes are encouragingly decreased to 62 and 282 arcsec, respectively. On such an AlN template, an ultra-thin AlN with a thickness of ~700 nm grown by MOCVD shows good quality, thus avoiding the epitaxial lateral overgrowth (ELOG) process in which 3–4 μm AlN is essential to obtain the flat surface and high crystalline quality. The 4-inch scaled wafer provides an avenue to match UVC-LED with the fabrication process of traditional GaN-based blue LED, therefore significantly improving yields and decreasing cost.

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Section: Resultsmentioning

confidence: 99%

Four-inch high quality crack-free AlN layer grown on a high-temperature annealed AlN template by MOCVD

et al. 2021

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“…Figure 7 presents the TEM images along the [1 0 −1 0] and [1 1 −2 0] AlN zone axes. At first, an interface was observed close to the interface between the sapphire and AlN/h-BN (around 10 nm from the interface), which should correspond to an inversion domain boundary between a bottom N-polar and a top Al-polar region, as always reported for face-to-face annealing of AlN on sapphire [ 25 , 26 ]. Moreover, a truncated pyramid-like cavity was found.…”

Section: Discussionmentioning

confidence: 60%

Crystalline Quality and Surface Morphology Improvement of Face-to-Face Annealed MBE-Grown AlN on h-BN

et al. 2022

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In this study, AlN epilayers were grown by ammonia-assisted molecular beam epitaxy on 3 nm h-BN grown on c-sapphire substrates. Their structural properties were investigated by comparing as-grown and postgrowth annealed layers. The role of annealing on the crystalline quality and surface morphology was studied as a function of AlN thickness and the annealing duration and temperature. Optimum annealing conditions were identified. The results of X-ray diffraction showed that optimization of the annealing recipe led to a significant reduction in the symmetric (0 0 0 2) and skew symmetric (1 0 −1 1) reflections, which was associated with a reduction in edge and mixed threading dislocation densities (TDDs). Furthermore, the impact on the crystalline structure of AlN and its surface was studied, and the results showed a transition from a surface with high roughness to a smoother surface morphology with a significant reduction in roughness. In addition, the annealing duration was increased at 1650 °C to further understand the impact on both AlN and h-BN, and the results showed a diffusion interplay between AlN and h-BN. Finally, an AlN layer was regrown on the top of an annealed template, which led to large terraces with atomic steps and low roughness.

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“…The advantage of the FIB-SEM system equipped with a low energy Ar-ion gun, EDS and EBSD detectors is to perform 'in-situ' chemical and crystallographic analyses of a 'fresh' sample surface immediately after surface preparation without any sample transfer. Sample preparation of TEM samples using the FIB-SEM-Ar + BIB system has been demonstrated, and improved images were successfully obtained (Stegmann et al, 2009;Kaur et al, 2016;Sato et al, 2017), therefore this system is also promising for EBSD analysis. While the milling rate of Ar-ion beam in this system is lower than that of standalone ion milling systems, optimization of FIB and Arion milling conditions is necessary to push forward the advantage of this system.…”

Section: Introductionmentioning

confidence: 98%

Developments in microfabrication of mineral samples for simultaneous EBSD–EDS analysis utilizing an FIB–SEM instrument: study on an S–type cosmic spherule from Antarctica

Kodama

Tomioka

Ito

et al. 2020

Journal of Mineralogical and Petrological Sciences

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A focused ion beam (FIB) scanning electron microscope (SEM) equipped with a low-energy Ar-ion gun, an electron back-scattered diffraction (EBSD) detector, and an energy dispersive spectrometer (EDS) was newly developed for microfabrication, followed by submicroscopic chemical and crystallographic analyses in an identical sample chamber. The surface condition of mineral samples requires extreme care during FIB milling process, especially for EBSD measurement, as the EBSD pattern is greatly affected by a damaged amorphous surface caused by a high-energy Ga-ion beam (30 keV), even when this damaged layer is only tens of nanometers in thickness. Low-energy broad Ar-ion beam milling (1 keV) overcomes this problem and allows us to obtain sharp EBSD patterns. We applied the microfabrication-analysis protocol to a cosmic spherule. Comprehensive mineralogical datasets from SEM images, X-ray elemental maps, and EBSD patterns were successfully obtained from a minute mineral sample, where conventional cutting and polishing processes are not possible.

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Electron microscopy analysis of microstructure of postannealed aluminum nitride template

Cited by 10 publications

References 33 publications

Four-inch high quality crack-free AlN layer grown on a high-temperature annealed AlN template by MOCVD

Four-inch high quality crack-free AlN layer grown on a high-temperature annealed AlN template by MOCVD

Crystalline Quality and Surface Morphology Improvement of Face-to-Face Annealed MBE-Grown AlN on h-BN

Developments in microfabrication of mineral samples for simultaneous EBSD–EDS analysis utilizing an FIB–SEM instrument: study on an S–type cosmic spherule from Antarctica

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