研究者詳細 - 天野　浩

Transferrable monolithic multicomponent system for near-ultraviolet optoelectronics

Qin Chuan, Gao Xumin, Yuan Jialei, Shi Zheng, Jiang Yuan, Liu Yuhuai, Wang Yongjin, Amano Hiroshi

APPLIED PHYSICS EXPRESS 11 巻 ( 5 ) 頁： 051201 2018年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Applied Physics Express

A monolithic near-ultraviolet multicomponent system is implemented on a 0.8-mm-diameter suspended membrane by integrating a transmitter, waveguide, and receiver into a single chip. Two identical InGaN/Al0.10Ga0.90N multiple-quantum well (MQW) diodes are fabricated using the same process flow, which separately function as a transmitter and receiver. There is a spectral overlap between the emission and detection spectra of the MQW diodes. Therefore, the receiver can respond to changes in the emission of the transmitter. The multicomponent system is mechanically transferred from silicon, and the wire-bonded transmitter on glass experimentally demonstrates spatial light transmission at 200 Mbps using non-return-to-zero on–off keying modulation.

DOI： 10.7567/APEX.11.051201

Correlation between dislocations and leakage current of p-n diodes on a free-standing GaN substrate

Usami Shigeyoshi, Ando Yuto, Tanaka Atsushi, Nagamatsu Kentaro, Deki Manato, Kushimoto Maki, Nitta Shugo, Honda Yoshio, Amano Hiroshi, Sugawara Yoshihiro, Yao Yong-Zhao, Ishikawa Yukari

APPLIED PHYSICS LETTERS 112 巻 ( 18 ) 頁： 182106 2018年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Applied Physics Letters

Dislocations that cause a reverse leakage current in vertical p-n diodes on a GaN free-standing substrate were investigated. Under a high reverse bias, dot-like leakage spots were observed using an emission microscope. Subsequent cathodoluminescence (CL) observations revealed that the leakage spots coincided with part of the CL dark spots, indicating that some types of dislocation cause reverse leakage. When etch pits were formed on the dislocations by KOH etching, three sizes of etch pits were obtained (large, medium, and small). Among these etch pits, only the medium pits coincided with leakage spots. Additionally, transmission electron microscopy observations revealed that pure screw dislocations are present under the leakage spots. The results revealed that 1c pure screw dislocations are related to the reverse leakage in vertical p-n diodes.

DOI： 10.1063/1.5024704

The 2018 GaN power electronics roadmap

Light output performance of red AlGaInP-based light emitting diodes with different chip geometries and structures

Oh Jeong-Tak, Lee Sang-Youl, Moon Yong-Tae, Moon Ji Hyung, Park Sunwoo, Hong Ki Yong, Song Ki Young, Oh Chan-Hyoung, Shim Jong-In, Jeong Hwan-Hee, Song June-O, Amano Hiroshi, Seong Tae-Yeon

OPTICS EXPRESS 26 巻 ( 9 ) 頁： 11194-11200 2018年4月

Amano H., Baines Y., Beam E., Borga Matteo, Bouchet T., Chalker Paul R., Charles M., Chen Kevin J., Chowdhury Nadim, Chu Rongming, De Santi Carlo, De Souza Maria Merlyne, Decoutere Stefaan, Di Cioccio L., Eckardt Bernd, Egawa Takashi, Fay P., Freedsman Joseph J., Guido L., Haeberlen Oliver, Haynes Geoff, Heckel Thomas, Hemakumara Dilini, Houston Peter, Hu Jie, Hua Mengyuan, Huang Qingyun, Huang Alex, Jiang Sheng, Kawai H., Kinzer Dan, Kuball Martin, Kumar Ashwani, Lee Kean Boon, Li Xu, Marcon Denis, Maerz Martin, McCarthy R., Meneghesso Gaudenzio, Meneghini Matteo, Morvan E., Nakajima A., Narayanan E. M. S., Oliver Stephen, Palacios Tomas, Piedra Daniel, Plissonnier M., Reddy R., Sun Min, Thayne Iain, Torres A., Trivellin Nicola, Unni V., Uren Michael J., Van Hove Marleen, Wallis David J., Wang J., Xie J., Yagi S., Yang Shu, Youtsey C., Yu Ruiyang, Zanoni Enrico, Zeltner Stefan, Zhang Yuhao

JOURNAL OF PHYSICS D-APPLIED PHYSICS 51 巻 ( 16 ) 頁： 163001 2018年4月

昇温脱離法によるInGaN表面上のCs層の解析

鹿島将央, 佐藤大樹, 小泉淳, 西谷智博, 本田善央, 天野浩, 飯島北斗, 目黒多加志

応用物理学会学術講演会講演予稿集 2018.1 巻 ( 0 ) 頁： 1670 - 1670 2018年3月

Growth of hexagonal boron nitride on sapphire substrate by pulsed-mode metalorganic vapor phase epitaxy

Yang Xu, Nitta Shugo, Nagamatsu Kentaro, Bae Si-Young, Lee Ho-Jun, Liu Yuhuai, Pristovsek Markus, Honda Yoshio, Amano Hiroshi

JOURNAL OF CRYSTAL GROWTH 482 巻 ( 15 ) 頁： 1 - 8 2018年1月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Crystal Growth

Hexagonal boron nitride (h-BN) was directly grown on sapphire substrate using alternating ammonia (NH3) and triethylboron (TEB) supply (pulsed mode) in metalorganic vapor phase epitaxy. The best condition is when just enough NH3 is supplied to fully convert the TEB within one cycle. Excess NH3 caused islands on h-BN film surface while a lack of NH3 does not form h-BN at all. The epitaxial relationship between grown h-BN layer and c-plane sapphire was confirmed to be [0001]h-BN∥[0001]sapphire and [10-10]h-BN∥[11-20]sapphire. It is known that, compared to AlN, BN requires higher V/III ratios for good crystallinity, which due to severe gas-phase reactions is difficult to achieve using continuous supply. Thus using pulsed mode the FWHM of the symmetric (0002) diffraction was almost halved and the growth rate was several times faster.

DOI： 10.1016/j.jcrysgro.2017.10.036

Electrical and Thermal Analysis of Vertical GaN-on-GaN PN Diodes

Yates, L; Pavlidis, G; Graham, S; Usami, S; Nagamatsu, K; Honda, Y; Amano, H

PROCEEDINGS OF THE 17TH IEEE INTERSOCIETY CONFERENCE ON THERMAL AND THERMOMECHANICAL PHENOMENA IN ELECTRONIC SYSTEMS (ITHERM 2018) 頁： 831 - 837 2018年

Theoretical Study of the Electronic Structure of Threading Edge Dislocations in GaN

Nakano Takashi, Araidai Masaaki, Shiraishi Kenji, Tanaka Atsushi, Honda Yoshio, Amano Hiroshi

GALLIUM NITRIDE AND SILICON CARBIDE POWER TECHNOLOGIES 8 86 巻 ( 12 ) 頁： 41 - 49 2018年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ECS Transactions

It is very important to fabricate high-quality GaN especially used for power devices. However, threading dislocations degrade the performance of GaN-based electronic devices. It is necessary to examine the electronic behavior at threading dislocations in GaN and to clarify the origin of the leakage current. As for theoretical studies, the electronic structure of threading dislocations in GaN is not fully understood. We investigated whether threading edge dislocations contribute to the leakage current or not. To do this, we used first principles calculations based on density functional theory (DFT) to examine the electronic structure at threading edge dislocations with Burgers vectors of 1/3[11-20]. We examined four core types of atomic structure at threading edge dislocations which contains about 200 atoms. Compared with dislocation line energies of each core configurations, it was found that the 5/7-atoms ring core and 8-atoms ring core are energetically stable. Then, we analyzed the electronic densities of states of each core configurations, and it was found that all types of core configurations at threading edge dislocations do not contribute to leakage current in n-type GaN-based devices.

DOI： 10.1149/08612.0041ecst

Low cost high voltage GaN polarization superjunction field effect transistors

DFT modeling of carbon incorporation in GaN(0001) and GaN(000(1)over-bar) metalorganic vapor phase epitaxy 査読有り

Pawel Kempisty, Yoshihiro Kangawa, Akira Kusaba, Kenji Shiraishi, Stanislaw Krukowski, Michal Bockowski, Koichi Kakimoto, and Hiroshi Amano

APPLIED PHYSICS LETTERS 111 巻頁： 141602/1-5 2017年10月

記述言語：英語掲載種別：研究論文（学術雑誌）

The carbon incorporation mechanism in GaN(0001) and GaN(000 (1) over bar) during MOVPE was investigated using density functional theory (DFT) calculations. The results confirm that the crucial factors for carbon incorporation are Fermi level pinning and accompanying surface band bending. In addition, the lattice symmetry has a strong dependence on the stability of carbon in a few subsurface layers, which results from interactions between the impurities and surface states. It was shown that these effects are responsible for facilitating or hindering the incorporation of impurities and dopants. The influence of diluent gas species (hydrogen or nitrogen) on carbon incorporation was discussed.

DOI： 10.1063/1.4991608

Initial leakage current paths in the vertical-type GaN-on-GaN Schottky barrier diodes

Liwen Sang, Bing Ren, Masatomo Sumiya, Meiyong Liao, Yasuo Koide, Atsushi Tanaka, Yujin Cho, Yoshitomo Harada, Toshihide Nabatame, Takashi Sekiguchi, Shigeyoshi Usami, Yoshio Honda, and Hiroshi Amano

APPLIED PHYSICS LETTERS 111 巻頁： 122102/1-5 2017年9月

記述言語：英語掲載種別：研究論文（学術雑誌）

Electrical characteristics of leakage current paths in vertical-type n-GaN Schottky barrier diodes (SBDs) on free-standing GaN substrates are investigated by using photon emission microscopy (PEM). The PEM mapping shows that the initial failure of the SBD devices at low voltages is due to the leakage current paths from polygonal pits in the GaN epilayers. It is observed that these polygonal pits originate from carbon impurity accumulation to the dislocations with a screw-type component by microstructure analysis. For the SBD without polygonal pits, no initial failure is observed and the first leakage appeals at the edge of electrodes as a result of electric field concentration. The mechanism of leakage at pits is explained in terms of trap assisted tunneling through fitting current-voltage characteristics.

DOI： 10.1063/1.4994627

Absolute technique for measuring internal electric fields in InGaN/GaN light-emitting diodes by electroreflectance applicable to all crystal orientations 査読有り

Tomoyuki Tanikawa, Kanako Shojiki, Ryuji Katayama, Shigeyuki Kuboya, Takashi Matsuoka, Yoshio Honda, and Hiroshi Amano

Applied Physics Express 10 巻頁： 082101/1-4 2017年8月

Kawai H., Yagi S., Hirata S., Nakamura F., Saito T., Kamiyama Y., Yamamoto M., Amano H., Unni V., Narayanan E. M. S.

PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE 214 巻 ( 8 ) 頁： 1600834/1-10 2017年8月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Physica Status Solidi (A) Applications and Materials Science

A comprehensive overview of the novel high voltage GaN field effect transistors (FETs) based on the Polarization Superjunction (PSJ) concept, and a cost-effective approach towards manufacturing these high performance devices are presented. Current challenges impeding wider adoption of GaN power switching transistors in applications, and the latest results of the scaled-up PSJ-FETs from POWDEC KK, are also discussed. The article also presents hard-switching characteristics of 400–800 V boost converter, constructed using a PSJ-FET grown on sapphire substrate, and the future direction of GaN power semiconductor technology based on monolithic integration for advanced power electronics.

DOI： 10.1002/pssa.201600834

Effect of dislocations on the growth of p-type GaN and on the characteristics of p-n diodes

Facet dependence of leakage current and carrier concentration in m-plane GaN Schottky barrier diode fabricated with MOVPE 査読有り

Atsushi Tanaka, Ousmane1 Barry, Kentaro Nagamatsu, Junya Matsushita, Manato Deki, Yuto Ando, Maki Kushimoto, Shugo Nitta, Yoshio Honda, and Hiroshi Amano

Phys. Status Solidi A 214 巻 ( 8 ) 頁： 1600829/1-5 2017年8月

記述言語：英語掲載種別：研究論文（学術雑誌）

In this study, GaN m-plane Schottky barrier diodes fabricated with a metalorganic vapor-phase epitaxy on a GaN substrate were investigated using emission microscope, photoluminescence, and cathodoluminescence. In addition, facet dependence of leakage current under reverse-biased condition was observed. We showed that the leakage-current distribution was caused by the facet dependence of the carrier concentration and oxygen concentration. These results can provide important suggestions for the fabrication of m-plane devices. (a) four-faceted hillocks on m-plane GaN MOVPE sample, facet dependence of (b) leakage current and (c) PL peak intensity of the m-plane GaN Schottky barrier diode.

DOI： 10.1002/pssa.201600829

Effect of dislocations on the growth of p-type GaN and on the characteristics of p–n diodes 招待有り査読有り

214 巻 ( 8 ) 頁： 1600837/1-5 2017年8月

Selective-area growth of doped GaN nanorods by pulsed-mode MOCVD: Effect of Si and Mg dopants 査読有り

Si-Young Bae, Kaddour Lekhal, Ho-Jun Lee, Jung-Wook Min, Dong-Seon Lee, Yoshio Honda, and Hiroshi Amano

Phys. Status Solidi B 254 巻 ( 8 ) 頁： 1600722/1-7 2017年8月

記述言語：英語掲載種別：研究論文（学術雑誌）

Injecting current with a uniform carrier concentration is important for applications with three-dimensional architectures such as vertical power devices or displays. In III-nitride nanostructures, dopants not only incorporate differently depending on the surface orientation but can also seriously affect the kinetic equilibrium shapes of the nanorods. Herein, we report selective-area growth of doped GaN nanorods grown by pulsed-mode metalorganic chemical vapor deposition. Two dopants, Si and Mg, were employed as donor and acceptor atoms, respectively, for a mono-doping approach. Furthermore, a mixed flow of Si and Mg was supplied for a co-doping approach. We compared the morphological effects and growth rates of each doped GaN nanorod array. Then, we proposed appropriate growth mechanisms for the doped GaN nanorods on the basis of our structural characterizations. These results might extend the morphological functionality of GaN nanorods by including doping and may also provide an appropriate foundation for the design of nanostructure-based electronic or photonic devices.

DOI： 10.1002/pssb.201600722

Decomposition of trimethylgallium and adduct formation in a metalorganic vapor phase epitaxy reactor analyzed by high-resolution gas monitoring system 査読有り

Kentaro Nagamatsu, Shugo Nitta, Zheng Ye, Hirofumi Nagao, Shinichi Miki, Yoshio Honda, and Hiroshi Amano

Phys. Status Solidi B 254 巻 ( 8 ) 頁： 1600737/1-4 2017年8月

Usami Shigeyoshi, Miyagoshi Ryosuke, Tanaka Atsushi, Nagamatsu Kentaro, Kushimoto Maki, Deki Manato, Nitta Shugo, Honda Yoshio, Amano Hiroshi

PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE 214 巻 ( 8 ) 2017年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physica Status Solidi (A) Applications and Materials Science

We investigate the influence of crystal defects on p-type GaN grown by metalorganic vapor phase epitaxy. Sets of p-type GaN films were grown on sapphire substrates and on free-standing GaN (F-GaN) substrates simultaneously using various Et-Cp2Mg flow rates. Although there is a difference of two orders of magnitude between the threading dislocation densities of p-type GaN grown on sapphire and F-GaN substrates, there is no significant difference in hole concentration. However, there are problems with the surface morphology of p-type GaN grown on sapphire. The deterioration of the surface was caused by the difference in nanopipe density. The electrical properties of a p–n junction diode formed on sapphire with a high density of nanopipes were observed using emission microscopy under both forward- and reverse-bias conditions. Our results demonstrate that the nanopipes are electrically inactive, and that other types of threading dislocation have more influence on the current–voltage characteristics.

DOI： 10.1002/pssa.201600837