研究者詳細 - 山下　善文

論文 - 山下　善文

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Enhancement of blue emission from GaN films and diodes by water vapor remote plasma treatment

Y. Kamiura, M. Ogasawara, K. Fukutani, T. Ishiyama, Y. Yamashita, T. Mitani, T. Mukai

PHYSICA B-CONDENSED MATTER 401 331 - 334 2007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：ELSEVIER SCIENCE BV

We have studied the effects of water vapor remote plasma treatment (H2O RPT) on emission from Si-doped and undoped n-type GaN films grown on c-face sapphire substrates by the atmospheric-pressure metalorganic chemical vapor deposition method. We found by photoluminescence (PL) spectroscopy at 77K that H2O RPT enhanced violet emission from the n-type GaN films, similarly to the previously observed enhancing effect on blue emission from Mg-doped p-type GaN films. We also observed that H2O RPT reduced the intensity of ESR signal comprising of two peaks detected at 4.2 K in undoped n-type films and increased their resistivity measured at room temperature. We ascribe the enhancing effect of H2O RPT to the passivation of non-radiative recombination centers by hydrogen produced by H2O RPT. We formed GaN p-n diodes from the layer structure of p-GaN:Mg/n-GaN:Si/sapphire, and carried out electroluminescence (EL) measurements of the diodes at 77 K. We observed that EL intensity was also enhanced by H2O RPT. (c) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physb.2007.08.180

Characteristic of strained SiGe film preventing hydrogen from penetrating into Si substrate detected by spreading resistance method

Yoshifumi Yamashita, Yoshifumi Sakamoto, Yoichi Kamiura, Takeshi Ishiyama

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 46 ( 4A ) 1622 - 1624 2007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：JAPAN SOC APPLIED PHYSICS

We investigated the resistivity depth profile of an episystem of a SiGe film on a Si substrate, which was hydrogen-treated by remote plasma by the spreading resistance method. We examined hydrogen penetration by monitoring the resistivity change of the Si substrate due to acceptor passivation by hydrogen. We found that the resistivity of the Si substrate covered by an as-grown SiGe film was not elevated. This indicates that it is extremely difficult for hydrogen atoms to penetrate strained SiGe epi-films. On the other hand, hydrogen atoms can easily penetrate Si films and annealed SiGe films. These results are presumably explained by the misfit strain of epifilms.

DOI： 10.1143/JJAP.46.1622

Charge-state and isotope effects on the recovery process of stress-induced reorientation of Pt-H-2 complex in silicon

Namula Bao, Yoichi Kamiura, Yoshifumi Yamashita, Takeshi Ishiyama

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 46 ( 3A ) 907 - 912 2007年3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：JAPAN SOC APPLIED PHYSICS

We have studied the local motion of hydrogen around a platinum impurity in Si, which was directly probed by measuring the recovery process of stress-induced reorientation of the Pt-H-2 complex by isothermal deep-level transient spectroscopy (IT-DLTS), We found that hydrogen more easily moved in the singly negative charge state of the Pt-H-2 complex than in the doubly negative charge state, and determined the activation energies for the recovery process to be 0.28 and 0.4 eV in the singly and doubly negative charge states, respectively, from a series of isothermal annealing experiments. We also found that the recovery rate of the Pt-D-2 complex in the singly negative charge state is 80% that of the Pt-H-2 complex with the same activation energy of 0.28 eV. This isotope effect clearly proves that both complexes have the same atomic configuration and that their recovery process is governed by the atomic jump of hydrogen (deuterium).

DOI： 10.1143/JJAP.46.907

Effects of hydrogen on resistivity depth profile of SiGe/p-Si detected by spreading resistance method

Yoshifumi Yamashita, Yoshifumi Sakamoto, Takeshi Ishiyama, Yoichi Kamiura

Proc. of The Forum on the Science and Technology of Silicon Materials 2007 209 - 216 2007年

The electronic states of platinum-hydrogen defects and hydrogen motion in Si observed by DLTS and IR techniques under uniaxial stress

K. Sato, Y. Kamiura, T. Ishiyama, Y. Yamashita

Proc. of The Forum on the Science and Technology of Silicon Materials 2007 258 - 274 2007年

Effects of compressive stress on the electronic states and atomic configurations of the Pt–H2 defect in silicon

Yoichi Kamiura, Kimihiro Sato, Yoshifumi Yamashita, Takeshi Ishiyama

Materials Science and Engineering B 134 ( 2-3 ) 213 - 217 2006年10月

Effects of hydrogen on depth profile of resistivity of SiGe on Si substrate

Y Yamashita, Y Kamiura, T Miyasako, T Shiotani, T Ishiyama

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 45 ( 5A ) 3994 - 3996 2006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：INST PURE APPLIED PHYSICS

We report that the resistivity of SiGe films deposited on a B-doped Si substrate by solid-source molecular beam epitaxy (MBE) is reduced by postgrowth hydrogen treatment and the subsequent annealing. This effect was observed near a bevel surface finished by mechanical polishing. Therefore, the damaged surface layer played an important role in this effect. The same reduction in the resistivity of the SiGe films was also observed by intentional supplying hydrogen during film deposition. These phenomena indicate that hydrogen assists the electrical activation of boron.

DOI： 10.1143/JJAP.45.3994

Local motion of hydrogen around platinum in Si

N Bao, Y Kamiura, Y Yamashita, T Ishiyama

PHYSICA B-CONDENSED MATTER 376 81 - 84 2006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：ELSEVIER SCIENCE BV

We have studied the local motion of hydrogen around platinum in Si from the recovery kinetics of stress-induced reorientation of the Pt-H-2 Complex. We evaluated the degree of alignment using isothermal DLTS (IT-DLTS) technique under a stress of 0.6 GPa along the < 111 > direction at 70 K where hydrogen Could not move. We observed the recovery at temperatures of 80-85 K only in the singly negative charge state of the Pt-H-2 complex, indicating the similar charge-state-dependent motion of hydrogen as in the stress-induced reorientation of the complex. We obtained an activation energy of 0.25 eV for the recovery process, being comparable with that for the stress-induced reorientation. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physb.2005.12.022

Stress-induced reorientation of the Pt-H-2 complex in Si

K Sato, Y Kamiura, Y Yamashita, T Ishiyama

PHYSICA B-CONDENSED MATTER 376 77 - 80 2006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：ELSEVIER SCIENCE BV

We have studied stress-induced reorientation of the Pt-H-2 complex in Si using isothermal deep-level transient spectroscopy (IT-DLTS) technique under uniaxial compressive stress. We have found that the intensity ratio of split components of the IT-DILTS peak for various magnitudes of applied stress up to 0.4 GPa is described by a Boltzmann factor, where the activation energy is proportional to the magnitude of the applied stress. The proportional factor is connected to an element of the piezospectroscopic tensor. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physb.2005.12.021

Effects of hydrogen treatment on strain relaxation of SiGe epi-layer on Ge substrate

Y Yamashita, R Nakagawa, Y Sakamoto, T Ishiyama, Y Kamiura

PHYSICA B-CONDENSED MATTER 376 204 - 207 2006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：ELSEVIER SCIENCE BV

Effects of hydrogen treatment on post-growth strain relaxation of GeSi epitaxial films on Ge substrate were studied. We found that pre-hydrogen treatment at room temperature enhanced strain relaxation during subsequent thermal treatment. We also confirmed that the relaxation enhancement effect became small as the annealing time was elongated and the temperature was raised. These results mean that the effect is more remarkable in the early stage of relaxation. In order to investigate the mechanism of this effect, threading dislocation velocity was measured. However, it was not enhanced by pre-hydrogenation. This fact strongly suggests that the relaxation enhancement effect was caused by increase of dislocation sources, which are attributed to hydrogen atoms incorporated into GeSi film. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physb.2005.12.054

Enhancement of photoluminescence at 1.54 mu m from Er in strained Si and SiGe

T Ishiyama, S Yoneyama, Y Yamashita, Y Kamiura, T Date, T Hasegawa, K Inoue, K Okuno

PHYSICA B-CONDENSED MATTER 376 122 - 125 2006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：ELSEVIER SCIENCE BV

We studied on the photoluminescence (PL) properties of Er in tensile-strained Si on a SiGe layer (Si:Er:O/SiGe) and compressively strained SiGe on a Si layer (SiGe:Er:O/Si) grown by molecular beam epitaxy (MBE). Er-related luminescence was observed around 1.54 mu m in both tensile- and compressively strained samples. The PL intensities of strained Si:Er:O/SiGe and SiGe:Er:O/Si samples were much stronger than those of unstrained Si:Er:O/Si samples. Moreover, intensive luminescence was observed in strained samples with low Er concentrations far below 10(18)CM(-3). The PL spectra of Si:Er:O/SiGe samples were broader than those of unstrained Si:Er:O/Si samples. On the other hand, no significant differences in the width between SiGe:Er:O/Si and unstrained samples were observed. These differences in the PL intensity between strained and unstrained samples strongly suggest that the optical activation of Er in Si and SiGe can be enhanced by the presence of strain. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physb.2005.12.031

Electron spin resonance of platinum pair complex in silicon

T Ishiyama, T Fukuda, Y Yamashita, Y Kamiura

PHYSICA B-CONDENSED MATTER 376 89 - 92 2006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：ELSEVIER SCIENCE BV

We investigated a Pt-Pt pair in Si by electron spin resonance (ESR) measurement. Two kinds of ESR spectra from Pt-Pt pairs which had been already reported were not detected. However, we observed other ESR spectrum of Pt-Pt pair. The ESR spectrum showed the hyperfine structure corresponding to two equivalent Pt atoms. The anisotropic g-tensor obtained by analyzing the angular dependence of the ESR signals indicated the orthorhombic (C-2 nu) symmetry with the g-values of g(x) = 2.11, g(y), = 2.3 1, g(z) = 2.09. The g(z) axis was along [001] direction. The g(y) and g(z) axes were along [110] and [1 (1) over bar0] directions, respectively. The ESR spectrum of Pt-Pt pair was observed in the sample only tinder illumination. This Suggests that a change in the charge state of Pt-Pt pair is caused by carrier excitation. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physb.2005.12.024

Enhancement of blue emission from Mg-doped GaN using remote plasma containing atomic hydrogen

Y Kamiura, M Kaneshiro, J Tamura, T Ishiyama, Y Yamashita, T Mitani, T Mukai

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 44 ( 28-32 ) L926 - L928 2005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：INST PURE APPLIED PHYSICS

We have found for the first time that blue emission from Mg-doped GaN was greatly enhanced by remote plasma treatment (RPT) with plasma containing atomic hydrogen, in particular, water vapor plasma, at low temperatures of 300-400 degrees C. The highest enhancing factor was twenty, achieved by water vapor RPT at 400 degrees C for 30 min. The enhanced blue emission was stable up to 500 degrees C, similarly to blue emission from as-grown samples, suggesting the same origin and mechanism. We have confirmed that the emission mechanism is donor-acceptor pair (DAP) recombination, and have concluded that RPT produces a hydrogen-related donor level at E-c - 0.37 eV involved in the DAP emission.

DOI： 10.1143/JJAP.44.L926

Observation of long relaxation from Fe-0(3d(8)) to Fe+(3d(7)) by electron spin resonance measurement

T Ishiyama, T Hiramatsu, Y Yamashita, Y Kamiura

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS 43 ( 1 ) 9 - 11 2004年1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：INST PURE APPLIED PHYSICS

We studied the change in the 3d-shell configurations of Fe in B-doped Si under illumination by electron spin resonance (ESR) measurement. ESR signals originating from Fe-i(+)(3d(7)) and Fe-i(0)(3d(8)) were observed in Fe- and B-doped Si. The ESR signal of Fe-i(+)(3d(7)) disappeared and the signal intensity of Fe-i(0)(3d(8)) increased under illumination. These changes of the ESR signals under illumination were caused by the change in the charge state from Fe-i(+)(3d(7)) to Fe-i(0)(3d(8)) due to the capture of an electron. Subsequently, the process of recovery from Fe-i(0)(3d(8)) to Fe-i(+)(3d(7)) due to the capture of a hole was observed after the light was turned off. We found that the relaxation time from Fe-i(0)(3d(8)) to Fe-i(+)(3d(7)) was approximately 30 s at 8 K. This was much longer than the lifetime of a free hole.

DOI： 10.1143/JJAP.43.9

Effect of uniaxial stress on the electronic state of a platinum-dihydrogen complex in silicon and charge-state-dependent motion of hydrogen during stress-induced reorientation

Y Kamiura, K Sato, Y Iwagami, Y Yamashita, T Ishiyama, Y Tokuda

PHYSICAL REVIEW B 69 ( 4 ) 2004年1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：AMER PHYSICAL SOC

We have combined isothermal deep-level transient spectroscopy (IT-DLTS) technique with the application of uniaxial compressive stress along <111> direction to study the effect of stress on the electronic state of a platinum-dihydrogen complex in Si and the kinetics of charge-state-dependent motion of hydrogen around the Pt atom during stress-induced reorientation. We have found that the application of stress splits the IT-DLTS peak into two components and the electronic energy of the short-time component increases linearly with <111> compressive stress as 35+/-4 meV/GPa, indicating antibonding character. We have also studied the reorientation kinetics of the complex under the applied stress, and have found that the defect aligned at 78-88 K in the configuration with the smallest activation energy of the level only when the level was not occupied by an electron. This indicates a clear charge-state effect on the local motion of hydrogen around the Pt atom, that is, hydrogen is mobile only in the singly negative charge state of the complex. We have estimated an activation energy 0.27 eV for the hydrogen motion around the Pt atom under a stress of 0.6 GPa. We have examined three structural models, among which a model where the two hydrogen atoms are directly bonded to the platinum atom may be the most plausible candidate. In this structure, defect reorientation needs no bond switching but only the rotation of the whole Pt-H-2 entity. A possible mechanism of the charge-state-dependent reorientation observed may be that if the electronic state with antibonding character is occupied by an electron, the two hydrogen atoms may be displaced outward, probably retarding their motion for the reorientation.

DOI： 10.1103/PhysRevB.69.045206

Comparative study of electronically controlled motion of hydrogen around carbon and platinum atoms in silicon

Y Kamiura, N Bao, K Sato, K Fukuda, Y Iwagami, Y Yamashita, T Ishiyama

HYDROGEN IN SEMICONDUCTORS 813 27 - 32 2004年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：MATERIALS RESEARCH SOCIETY

We have studied the local motion of hydrogen in the neighborhood of carbon and platinum impurities by observing the stress-induced reorientation and subsequent recovery of two H-related (H-C and Pt-H-2) complexes in Si, using deep-level transient spectroscopy (DLTS) under uniaxial compressive stress. We notice two interesting differences in hydrogen motion around carbon and platinum atoms. The first one is a difference in the temperature where stress-induced reorientation occurs. That of the H-C complex occurs at high temperatures above 250 K, while it occurs at low temperatures around 80 K for the Pt-H2 complex. The second difference is the effect of charge state of the complexes on their stress-induced reorientation and subsequent recovery. It occurs preferentially when an electron occupies the level of the H-C complex, but the Pt-H-2 complex has the reverse effect of level occupancy. These differences are discussed from viewpoint of different atomic configurations and electronic states of two H-related complexes.

Strain-enhanced photoluminescence of Er in strained Si and SiGe layers

T. Ishiyama, Y. Kamiura, S. Yoneyama, Y. Yamashita, T. Date, T. Hasegawa, K. Inoue, K. Okuno

Proceedings of The 4th International Symposium on Advanced Science and Technology of Silicon Materials (JSPS Si Symposium) 2004年

Enhancing effect of tensile strain on photoluminescence of Er in Si on a SiGe layer

T Ishiyama, M Yoshida, Y Yamashita, Y Kamiura, T Date, T Hasegawa, K Inoue, K Okuno

PHYSICA B-CONDENSED MATTER 340 818 - 822 2003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：ELSEVIER SCIENCE BV

We studied on the effect of the strain on photoluminescence (PL) properties of Er-doped Si on a SiGe layer (Si:Er:O/SiGe) and Er-doped SiGe on a Si layer (SiGe:Er:O/Si) grown by molecular beam epitaxy. Er-related luminescence was observed around 1.54 mum in all the samples. The PL spectra of the Si:Er:O/SiGe samples are much broader and stronger than those of the Si:Er:O/Si samples prepared as reference. Moreover, the intensive luminescence was observed in the Si:Er:O/SiGe sample that had much lower Er concentration of about 2.5 x 10(16) cm(-3). On the other hand, the significant differences in the PL spectra between the SiGe:Er:O/Si and Si:Er:O/Si samples were not observed. These indicate that the tensile strained Si enhances the optical activation of Er. (C) 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physb.2003.09.225

Study of the deep level related to a platinum-dihydrogen complex in Si by capacitance transient spectroscopy under uniaxial stress

Y Kamiura, Y Iwagami, K Fukuda, Y Yamashita, T Ishiyama, Y Tokuda

MICROELECTRONIC ENGINEERING 66 ( 1-4 ) 352 - 357 2003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：ELSEVIER SCIENCE BV

We have applied a novel technique to combine isothermal deep-level transient spectroscopy (DLTS) with the application of uniaxial compressive stress to studying the structure of a platinum- and hydrogen-related defect, which has a gap state at 0.14 eV below the conduction band in Si. The application of <100> and <111> stresses split the DLTS peak of the defect into two components with intensity ratios of 23:1 and 1.1:1, respectively, which were ratios of short- to long-time components. Under <110> stress, the peak split into three components with an intensity ratio of 0.8:3.7:1. Comparing this splitting pattern to the piezospectroscopic theory of Kaplyanskii, we have uniquely determined that the defect has the orthorhombic symmetry with the C-2v point group, and have identified the defect as the Pt-H-2 complex previously identified by Uftring et al. [Phys. Rev. B 51 (1995) 9612]. We also observed that the defect was reoriented above 80 K along the applied uniaxial stress. Such reorientation occurred only when the defect level was not occupied by an electron. Our observation strongly suggests that the local motion of hydrogen around the Pt atom is remarkably affected by the charge state of the defect. (C) 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0167-9317(02)00941-3

Effects of hydrogen atoms on postannealing of phosphorus-ion implanted silicon

Y Yamashita, Y Kamiura, Yamamoto, I, T Ishiyama, Y Sato

JOURNAL OF APPLIED PHYSICS 93 ( 1 ) 134 - 138 2003年1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：AMER INST PHYSICS

The ion implantation process used in silicon device processing needs a postannealing at as high as 1000 degreesC to recover the damages induced by high-energy ion bombardment and to electrically activate implanted impurities. We developed a postannealing treatment using remote-hydrogen plasma to reduce the annealing temperature. We found that our postannealing treatment more greatly reduced the resistivity of the surface region, which was very high just after implantation. The dependence of resistivity-reduction rate on annealing temperature was weaker for the annealing with hydrogen plasma than for the normal annealing. Therefore the enhancing effect by hydrogen was remarkable at lower temperature in the range of 250-350 degreesC. The less the dose quantity was, the stronger the enhancing effect was observed. The postannealing using hydrogen plasma with the power of 50 W at 300 degreesC for 2 h showed almost the same performance as the usual rapid thermal annealing process at 1000 degreesC for 30 s. (C) 2003 American Institute of Physics.

DOI： 10.1063/1.1527713

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