研究者詳細 - 堀田　昌宏

論文 - 堀田　昌宏

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Estimation of Impact Ionization Coefficient in GaN by Photomulitiplication Measurement Utilizing Franz-Keldysh Effect 査読有り

Maeda, T; Narita, T; Ueda, H; Kanechika, M; Uesugi, T; Kachi, T; Kimoto, T; Horita, M; Suda, J

2019 31ST INTERNATIONAL SYMPOSIUM ON POWER SEMICONDUCTOR DEVICES AND ICS (ISPSD) 2019-May 巻頁： 59 - 62 2019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：Proceedings of the International Symposium on Power Semiconductor Devices and ICs

A valanche multiplication characteristics in GaN p-n junction diodes (PNDs) under high reverse bias conditions were investigated. The GaN-on-GaN PNDs with double-side-depleted shallow bevel termination, which showed low reverse leakage current and excellent avalanche capability, were used for the measurements. Under sub-bandgap light illumination, the photocurrents induced by Franz-Keldysh (FK) effect, which can be well reproduced by the theoretical calculations of the optical absorption, and their avalanche multiplications were observed. The multiplication factors were extracted as the ratios of the experimental photocurrents to the calculated FK-induced photocurrent. Under an assumption of equal impact ionization coefficients of electrons and holes, the electric-field dependence of an impact ionization coefficient in GaN were estimated.

DOI： 10.1109/ispsd.2019.8757676

Web of Science

Scopus

Impact Ionization Coefficients in GaN Measured by Above- and Sub-Eg Illuminations for p-/n+ Junction

Maeda, T; Narita, T; Yamada, S; Kachi, T; Kimoto, T; Horita, M; Suda, J

2019 IEEE INTERNATIONAL ELECTRON DEVICES MEETING (IEDM) 2019年

The origin of carbon-related carrier compensation in p-type GaN layers grown by MOVPE

Narita, T; Tomita, K; Tokuda, Y; Kogiso, T; Horita, M; Kachi, T

JOURNAL OF APPLIED PHYSICS 124 巻 ( 21 ) 2018年12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：Journal of Applied Physics

The role of carbon impurities in p-type GaN layers grown by metalorganic vapor phase epitaxy (MOVPE) was investigated. The lightly Mg-doped (∼1017 cm-3) p-type GaN samples with different carbon concentration [C] were prepared by controlling growth temperature and pressure. Temperature-dependent Hall-effect analyses exhibited an increase in donor concentration with increasing [C]. The low-temperature mobility also decreased with increasing [C], as a result of mobility limitation due to ionized impurity scattering. These results show that carbon atoms in MOVPE-grown p-GaN layers act as ionized donors and cause carrier compensation. Deep-level transient spectroscopy (DLTS) using bias pulses detected the existence of Hd traps (EV +0.88 eV) arising from the 0/-1 charge state of carbon on nitrogen sites (CN). The concentrations of Hd traps closely corresponded to [C] values in p-type GaN layers. Employing low-frequency capacitance DLTS to avoid carrier freeze-out at low temperatures, we newly discovered the Ha trap (EV +0.29 eV) whose concentration was directly proportional to the [C] value. These findings suggest that the Ha trap originates from CN identical to the Hd trap. Based on prior theoretical calculations of energy levels, the Ha trap can reasonably be assigned to a +1/0 donor state of CN. These results strongly suggest that a CN having two different charged states can compensate an electron and a hole in n-type and p-type GaN layers, respectively.

DOI： 10.1063/1.5057373

Web of Science

Scopus

Phonon-assisted optical absorption due to Franz-Keldysh effect in 4H-SiC p-n junction diode under high reverse bias voltage

Maeda, T; Chi, XL; Horita, M; Suda, J; Kimoto, T

APPLIED PHYSICS EXPRESS 11 巻 ( 9 ) 2018年9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

Photocurrent in a 4H-SiC p-n junction diode under illumination with sub-bandgap light was investigated. Under a high reverse bias condition, the photocurrent significantly increased with an increase in the reverse bias voltage. We calculated the photocurrent taking into consideration the phonon-assisted optical absorption due to the Franz-Keldysh effect. The calculated photocurrent showed good agreement with the experimental results. The photocurrent also increased at elevated temperatures, which could be quantitatively explained by the redshift of the 4H-SiC absorption edge (the shrinkage of the bandgap) and the increase in the phonon occupation number with rising temperature.

DOI： 10.7567/APEX.11.091302

Web of Science

Scopus

Accurate method for estimating hole trap concentration in n-type GaN via minority carrier transient spectroscopy

Kanegae, K; Horita, M; Kimoto, T; Suda, J

APPLIED PHYSICS EXPRESS 11 巻 ( 7 ) 2018年7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

We propose an analysis method for the accurate estimation of the hole trap (H1, EV + 0.85 eV) concentration in n-type GaN via minority carrier transient spectroscopy (MCTS). The proposed method considers both the hole occupation during a filling (current injection) period and the quick carrier recombination via the hole traps near the depletion layer edge immediately after a reverse bias is applied. The reverse bias voltage dependence of the MCTS spectrum indicates that an accurate trap concentration, as well as the hole diffusion length and electron capture cross section of the hole trap, can be determined.

DOI： 10.7567/APEX.11.071002

Web of Science

Scopus

Characterization of carrier concentration and mobility of GaN bulk substrates by Raman scattering and infrared reflectance spectroscopies

Kanegae, K; Kaneko, M; Kimoto, T; Horita, M; Suda, J

JAPANESE JOURNAL OF APPLIED PHYSICS 57 巻 ( 7 ) 2018年7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：Japanese Journal of Applied Physics

n-Type GaN bulk substrates with carrier concentrations (n) of 1016-1020 cm%3 were characterized by Raman scattering (350-5000 cm-1) and infrared reflectance (400-5000 cm%1) spectroscopies. Experimental spectra were fitted with the curves calculated from the dielectric function and carrier concentration and mobility of the GaN bulk. The obtained values agree well with the values from Hall-effect measurements for n of 1016-1019 cm-3 in Raman scattering measurements and for n of 1018-1020 cm-3 in infrared reflectance measurements.

DOI： 10.7567/JJAP.57.070309

Web of Science

Scopus

Franz-Keldysh effect in GaN p-n junction diode under high reverse bias voltage

Maeda, T; Narita, T; Kanechika, M; Uesugi, T; Kachi, T; Kimoto, T; Horita, M; Suda, J

APPLIED PHYSICS LETTERS 112 巻 ( 25 ) 2018年6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

Photocurrent induced by sub-bandgap light absorption due to the Franz-Keldysh effect was observed in GaN p-n junction diodes under a high reverse bias voltage. The photocurrent increased with the reverse bias voltage and the increase was found to be more significant as the wavelength approached the absorption edge of GaN. The photocurrent was calculated with consideration of light absorption induced by the Franz-Keldysh effect in the depletion layer. The calculated curves showed excellent agreement with the experimental curves. The photocurrent also increased with an increase in temperature and this could be quantitatively explained by the red-shift of the GaN absorption edge with the increase in temperature.

DOI： 10.1063/1.5031215

Web of Science

Scopus

Sources of carrier compensation in metalorganic vapor phase epitaxy-grown homoepitaxial n-type GaN layers with various doping concentrations

Sawada, N; Narita, T; Kanechika, M; Uesugi, T; Kachi, T; Horita, M; Kimoto, T; Suda, J

APPLIED PHYSICS EXPRESS 11 巻 ( 4 ) 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 Express

The source of carrier compensation in metalorganic vapor phase epitaxy (MOVPE)-grown n-type GaN was quantitatively investigated by Halleffect measurement, deep-level transient spectroscopy, and secondary ion mass spectrometry. These analysis techniques revealed that there were at least three different compensation sources. The carrier compensation for samples with donor concentrations below 5 1016 cm3 can be explained by residual carbon and electron trap E3 (EC % 0.6 eV). For samples with higher donor concentrations, we found a proportional relationship between donor concentration and compensating acceptor concentration, which resulted from a third source of compensation. This is possibly due to the self-compensation effect.

DOI： 10.7567/APEX.11.041001

Web of Science

Scopus

Parallel-Plane Breakdown Fields of 2.8-3.5 MV/cm in GaN-on-GaN p-n Junction Diodes with Double-Side-Depleted Shallow Bevel Termination 査読有り

Maeda, T; Narita, T; Ueda, H; Kanechika, M; Uesugi, T; Kachi, T; Kimoto, T; Horita, M; Suda, J

2018 IEEE INTERNATIONAL ELECTRON DEVICES MEETING (IEDM) 2018年

Characterization of lightly-doped n- and p-type homoepitaxial GaN on free-standing substrates 招待有り査読有り

Horita M., Suda J.

IMFEDK 2017 - 2017 International Meeting for Future of Electron Devices, Kansai 頁： 86 - 87 2017年7月

記述言語：英語出版者・発行元：IMFEDK 2017 - 2017 International Meeting for Future of Electron Devices, Kansai

Hall-effect measurements for n-type and p-type GaN with low doping concentration are presented. The GaN layers were grown by metal-organic vapor phase epitaxy on hydride-vapor-phase-epitaxy-grown free-standing GaN substrates. For n-GaN, the origin of acceptor which compensating donor is not only C but also native defects for the Si doping concentration of 1016 cm-3 level. The electron mobility is mainly limited by ionized impurity scattering or polar optical phonon scattering in the temperature less or higher than 200 K, respectively. For p-GaN, lightly Mg doping of mid 1016 cm-3 was achieved, which shows the donor concentration of 3.2×1016 cm-3 and the mobility of 31 cm2/Vs at 300 K.

DOI： 10.1109/IMFEDK.2017.7998055

Scopus

Solution-derived SiO2 gate insulator formed by CO2 laser annealing for polycrystalline silicon thin-film transistors 査読有り

Daisuke Hishitani, Masahiro Horita, Yasuaki Ishikawa, Hiroshi Ikenoue, Yukiharu Uraoka

Japanese Journal of Applied Physics 56 巻 ( 5 ) 2017年5月

Temperature dependence of barrier height in Ni/n-GaN Schottky barrier diode 査読有り

Takuya Maeda, Masaya Okada, Masaki Ueno, Yoshiyuki Yamamoto, Tsunenobu Kimoto, Masahiro Horita, Jun Suda

Applied Physics Express 10 巻 ( 5 ) 2017年5月

Hall-effect measurements of metalorganic vapor-phase epitaxy-grown p-type homoepitaxial GaN layers with various Mg concentrations 査読有り

Masahiro Horita, Shinya Takashima, Ryo Tanaka, Hideaki Matsuyama, Katsunori Ueno, Masaharu Edo, Tokio Takahashi, Mitsuaki Shimizu, Jun Suda

Japanese Journal of Applied Physics 56 巻 ( 3 ) 2017年3月

Characterization of lightly-doped n- and p-type homoepitaxial GaN on free-standing substrates 招待有り査読有り

Horita, M; Suda, J

2017 IEEE INTERNATIONAL MEETING FOR FUTURE OF ELECTRON DEVICES, KANSAI (IMFEDK) 頁： 86 - 87 2017年

Characterization of lightly-doped n- and p-type homoepitaxial GaN on free-standing substrates

Horita Masahiro, Suda Jun

2017 IEEE INTERNATIONAL MEETING FOR FUTURE OF ELECTRON DEVICES, KANSAI (IMFEDK) 頁： 86-87 2017年

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