Spatially resolved cathodoluminescence study on AlGaN layer fabricated by air‐bridged lateral epitaxial growth

Ishibashi, Akihiro; Kawaguchi, Yôichi; Sugahara, Gaku; Shimamoto, Toshitaka; Yokogawa, Toshiya; Yamada, Yoichi; Ueki, Yusuke; Nakamura, Kohzo; Taguchi, Tsunemasa

doi:10.1002/pssb.200405073

Cited by 5 publications

(3 citation statements)

References 16 publications

(12 reference statements)

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“…The heights of the voids in the HVAB structure markedly exceeds that of those in the conventional air-bridged LEO. [7][8][9] Figure 2 presents cross-sectional and plane-view CL images of conventional pendeo and HVAB structures. The crosssectional CL images in Figs.…”

Section: Air-bridged and Dot Air-bridged Epitaxial Lateral Overgrowthmentioning

confidence: 99%

“…[6] Kidoguchi et al proposed a new method of lateral growth, called air-bridged LEO, which improves on the wing tilting caused by conventional selective epitaxy. [7][8][9] Dry etching and standard photolithography were adopted herein to form trenches in a GaN template, and the sidewall of the GaN trenches was covered with a dielectric mask, such as SiN x or SiO 2 ,in an air-bridged LEO structure. After GaN had regrown, the voids in the air-bridged structure were buried in the coalesced GaN wings.…”

Section: Air-bridged and Dot Air-bridged Epitaxial Lateral Overgrowthmentioning

confidence: 99%

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High quality free-standing GaN thick-films prepared by hydride vapor phase epitaxy using stress reducing techniques

et al. 2009

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As one of the most mature techniques for manufacturing free-standing GaN substrates, hydride vapor phase epitaxy (HVPE) always encounters problems associated with residue thermal stress, such as GaN bending and cracking during and after growth. This work presents a patterning approach and a non-patterning approach to reduce stress in thick GaN films grown on sapphires by HVPE. The patterning approach, forming dot air-bridged structures, adopted standard photolithography to fabricate hexagonally aligned patterns of dots on GaN templates. Following HVPE growth, regular voids were formed and buried in the GaN thick-films. These voids helped to relax the stress in the GaN thick-films. In the non-patterning approach, thick GaN films were simply grown at a specially set sequence of ramping temperatures during HVPE growth without any patterned structure. This temperature-ramping technique, gives crack-free high-quality 2"-diameter GaN films, thicker than 250 μm, on sapphires in high yields. These thick GaN films can be separated from sapphire using conventional laser-induced lift-off processes, which can be followed by subsequent HVPE regrowths. A 600 μm-thick free-standing GaN films has a typical dislocation density of around 4×10 6 cm -2 with a full width at half maximum (FWHM) in the high resolution X-ray diffraction (HRXRD) spectrum of GaN (002) of around 150 arcsec.The residual stress in the thick GaN films was analyzed by micro-Raman spectroscopy. The effectiveness of the patterning and the non-patterning techniques in reducing the strain in GaN films is discussed. The advantages and weaknesses of the patterning and the non-patterning techniques will be elucidated.

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Section: Air-bridged and Dot Air-bridged Epitaxial Lateral Overgrowthmentioning

confidence: 99%

Section: Air-bridged and Dot Air-bridged Epitaxial Lateral Overgrowthmentioning

confidence: 99%

High quality free-standing GaN thick-films prepared by hydride vapor phase epitaxy using stress reducing techniques

et al. 2009

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“…We have reported a CL study of ABLEG-AlGaN films, in which we showed that there are mainly three parts of aluminum inhomogeneity in ABLEG-AlGaN wing films. 18) We suggested that the aluminum inhomogeneity is due to three factors: (1) the different growth rates between the lateral and vertical directions, (2) the aluminum adatom diffusion on the (0001) and ( 1120) facets, and (3) the different effective growth temperatures of the ( 0001) and (11 20) facets. In this work, we examined further the spatial inhomogeneity of aluminum content in the main three parts of ABLEG-AlGaN films with various mask widths.…”

Section: Introductionmentioning

confidence: 99%

Spatial Inhomogeneity of Aluminum Content in Air-Bridged Lateral Epitaxially Grown AlGaN Ternary Alloy Films Probed by Cross-Sectional Scanning Near-Field Optical Microscopy

Ishibashi

Murotani

Yokogawa

et al. 2012

Jpn. J. Appl. Phys.

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We systematically studied spatial inhomogeneity of aluminum content in air-bridged lateral epitaxially grown (ABLEG) AlGaN ternary alloy films by high-resolution photoluminescence mapping probed with cross-sectional scanning near-field optical microscopy (SNOM). We observed the content changes along the vertical <0001> and the horizontal <112̄0> growth directions in AlGaN films with four different mask widths. The spatial inhomogeneity was determined by considering the following factors: the different growth rates of the lateral and vertical directions, the aluminum and gallium adatom supplies from a gas that depend on mask width, and the aluminum and gallium adatom diffusions on the (0001) and (112̄0) facets.

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Progress on AlGaN-based solar-blind ultraviolet photodetectors and focal plane arrays

et al. 2021

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Solar-blind ultraviolet (UV) photodetectors (PDs) have attracted tremendous attention in the environmental, industrial, military, and biological fields. As a representative III-nitride material, AlGaN alloys have broad development prospects in the field of solar-blind detection due to their superior properties, such as tunable wide bandgaps for intrinsic UV detection. In recent decades, a variety of AlGaN-based PDs have been developed to achieve high-precision solar-blind UV detection. As integrated optoelectronic technology advances, AlGaN-based focal plane arrays (FPAs) are manufactured and exhibit outstanding solar-blind imaging capability. Considering the rapid development of AlGaN detection techniques, this paper comprehensively reviews the progress on AlGaN-based solar-blind UV PDs and FPAs. First, the basic physical properties of AlGaN are presented. The epitaxy and p-type doping problems of AlGaN alloys are then discussed. Diverse PDs, including photoconductors and Schottky, metal–semiconductor–metal (MSM), p-i-n, and avalanche photodiodes (APDs), are demonstrated, and the physical mechanisms are analyzed to improve device performance. Additionally, this paper summarizes imaging technologies used with AlGaN FPAs in recent years. Benefiting from the development of AlGaN materials and optoelectronic devices, solar-blind UV detection technology is greeted with significant revolutions.

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Spatially resolved cathodoluminescence study on AlGaN layer fabricated by air‐bridged lateral epitaxial growth

Cited by 5 publications

References 16 publications

High quality free-standing GaN thick-films prepared by hydride vapor phase epitaxy using stress reducing techniques

High quality free-standing GaN thick-films prepared by hydride vapor phase epitaxy using stress reducing techniques

Spatial Inhomogeneity of Aluminum Content in Air-Bridged Lateral Epitaxially Grown AlGaN Ternary Alloy Films Probed by Cross-Sectional Scanning Near-Field Optical Microscopy

Progress on AlGaN-based solar-blind ultraviolet photodetectors and focal plane arrays

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