MOVPE growth of nitrogen- and aluminum-polar AlN on 4H-SiC

Lemettinen, Jori; Okumura, Hironori; Kim, Iurii; Rudziński, M.; Grzonka, J.; Palacios, Tomás; Suihkonen, Sami

doi:10.1016/j.jcrysgro.2018.02.020

Cited by 36 publications

(26 citation statements)

References 41 publications

(59 reference statements)

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“…The FWHMs increase with increasing the V/III ratio, suggesting degrading crystalline quality. Based on our previous study we believe this to be the optimum V/III ratio since hexagonal hillocks were formed when V/III ratio was decreased below 1000 [20]. We consider that the step flow growth mode contributes to high crystalline quality.…”

Section: Resultsmentioning

confidence: 78%

“…In a previous study, we have shown that the formation of hexagonal hillocks can be suppressed in N-polar AlN growth by using a low growth rate of 0.1 µm/h together with an increased temperature of 1150 • C [20]. In this paper we study the effect of miscut angle of C-face 4H-SiC substrate on MOVPE growth of N-polar AlN under various growth conditions.…”

Section: Introductionmentioning

confidence: 96%

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MOVPE growth of N-polar AlN on 4H-SiC: Effect of substrate miscut on layer quality

Lemettinen

Okumura

Kim

et al. 2018

Journal of Crystal Growth

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We present the effect of miscut angle of SiC substrates on N-polar AlN growth. The N-polar AlN layers were grown on C-face 4H-SiC substrates with a miscut towards <1100 > by metal-organic vapor phase epitaxy (MOVPE). The optimal V/III ratios for high-quality AlN growth on 1 • and 4 • miscut substrates were found to be 20000 and 1000, respectively. MOVPE grown N-polar AlN layer without hexagonal hillocks or step bunching was achieved using a 4H-SiC substrate with an intentional miscut of 1 • towards <1100 >. The 200-nm-thick AlN layer exhibited X-ray rocking curve full width half maximums of 203 arcsec and 389 arcsec for (002) and (102) reflections, respectively. The root mean square roughness was 0.43 nm for a 2 µm × 2 µm atomic force microscope scan.

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Section: Resultsmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 96%

MOVPE growth of N-polar AlN on 4H-SiC: Effect of substrate miscut on layer quality

Lemettinen

Okumura

Kim

et al. 2018

Journal of Crystal Growth

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“…Other studies have also confirmed that N-polar AlN usually coexists with Al-polar AlN IDs, meaning that AlN film grown on sapphire substrate generally exists in two forms: Al-polar AlN and mixed-polar AlN. To realize large-area pure N-polar AlN, C-face SiC substrate may be the better choice [24]. The mixed-polar AlN can be confirmed by the KOH solution etching because N-polar AlN has an obvious faster etching rate compared with Al-polar AlN.…”

Section: Polarity Control Of Aln/sapphire Templatementioning

confidence: 88%

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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“…AlN can be grown in two forms: film and bulk. AlN films have been fabricated by various methods, such as metal–organic vapour-phase epitaxy (MOVPE) 4 , 5 , hydride vapour phase epitaxy (HVPE) 6 , 7 , pulsed laser deposition (PLD) 8 , 9 , molecular beam epitaxy (MBE) 10 , 11 , or sputtering 12 , 13 , to improve its crystalline quality, surface area, growth rate, or lower its processing temperature. Annealing techniques have been demonstrated to improve the crystalline quality of AlN films 14 – 16 .…”

Section: Introductionmentioning

confidence: 99%

AlN formation by an Al/GaN substitution reaction

Noorprajuda

Ohtsuka

Adachi

et al. 2020

Sci Rep

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Aluminium nitride (Aln) is a promising semiconductor material for use as a substrate in high-power, high-frequency electronic and deep-ultraviolet optoelectronic devices. We study the feasibility of a novel Aln fabrication technique by using the Al/Gan substitution reaction method. the substitution method we propose here consists of an Al deposition process on a Gan substrate by a sputtering technique and heat treatment process. the substitution reaction (Al + Gan = Aln + Ga) is proceeded by heat treatment of the Al/Gan sample, which provides a low temperature, simple and easy process. C-axis-oriented Aln layers are formed at the Al/Gan interface after heat treatment of the Al/Gan samples at some conditions of 1473-1573 K for 0-3 h. A longer holding time leads to an increase in the thickness of the AlN layer. The growth rate of the AlN layer is controlled by the interdiffusion in the Aln layer. Aluminium nitride (AlN) is a promising semiconductor material for use as a substrate in high-power, highfrequency electronic and optoelectronic devices. It can be used as a substrate in AlGaN-based ultraviolet C (UV-C) optoelectronic devices owing to its wide bandgap (above 6 eV) 1 , UV transparency 2 , and close lattice constant with that of AlGaN 3. AlN can be grown in two forms: film and bulk. AlN films have been fabricated by various methods, such as metal-organic vapour-phase epitaxy (MOVPE) 4,5 , hydride vapour phase epitaxy (HVPE) 6,7 , pulsed laser deposition (PLD) 8,9 , molecular beam epitaxy (MBE) 10,11 , or sputtering 12,13 , to improve its crystalline quality, surface area, growth rate, or lower its processing temperature. Annealing techniques have been demonstrated to improve the crystalline quality of AlN films 14-16. To facilitate the further development of AlN crystal growth, several researchers have developed original and unconventional techniques. For example, the pyrolytic transportation method 17 , the liquid phase epitaxy (LPE) method using a Ga-Al binary solution 18 , Al-Sn flux growth 19 , AlN fabrication by using Al and Li 3 N solid sources 20 , and elementary-source vapour-phase epitaxy (EVPE) 21 have been demonstrated. In the pyrolytic transportation method 17 , α-Al 2 O 3 is used as an Al-source material, and it is heated at 2223 K to form Al 2 O gas in the nitrogen gas flow. The Al 2 O gas is transported to the growth zone to react with nitrogen gas at 2023 K on a sintered AlN plate for 30 h, which yields a rod-like AlN crystal (48-mm long). The advantages of this method are an economically friendly α-Al 2 O 3 source and good crystalline quality of AlN. Wu et al. 21 used metallic Al and nitrogen gas as source materials to grow an AlN crystal, which they called elementary-source vapour-phase epitaxy (EVPE). They grew the AlN with a growth rate of 18 μm/h under an optimum growth zone temperature of 1823 K. The advantages of this method are that it is conducted at a temperature lower than that of the sublimation method using no hazardous gas. Regarding the LPE methods, Adachi et al. 18 grew a 1-µm-...

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MOVPE growth of nitrogen- and aluminum-polar AlN on 4H-SiC

Cited by 36 publications

References 41 publications

MOVPE growth of N-polar AlN on 4H-SiC: Effect of substrate miscut on layer quality

MOVPE growth of N-polar AlN on 4H-SiC: Effect of substrate miscut on layer quality

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

AlN formation by an Al/GaN substitution reaction

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