H. Aharoni

Ben-Gurion University of the Negev, Beersheba, Southern District, Israel

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Publications (47)43.22 Total impact

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    ABSTRACT: An advanced approach for the growth of thin and ultra-thin oxide and nitride films at low temperatures (400?C) for the fabrication of future scaled-down semiconductor electron devices is presented. This technique presents an alternative to the existing conventional thermal techniques currently employed in the IC industry, which utilize high-temperatures (800?C-1000?C) for the growth of both SiO<sub>2</sub> and Si<sub>3</sub>N<sub>4</sub> films. An alternative is needed since the high temperature range given above limits further down-scaling possibilities of semiconductor electronic devices. In this paper, the structure, operational principles, and performance of a microwave-excited high-density (> 10<sup>12</sup> cm<sup>-3</sup>) plasma system, which utilizes low bombardment inert gas ion energies (<7 eV), low plasma potential (<10 V), and low electron temperature (<1 eV), is described, which yields high-integrity SiO<sub>2</sub> and Si<sub>3</sub>N<sub>4</sub> films grown at 400?C. The films grown by this technique were previously shown by us to demonstrate comparable or superior performance with respect to SiO<sub>2</sub> films grown by the conventional thermal method at much higher temperatures (1000?C). The specific issue which this paper addresses is the problem of the growth rate of these films, which are grown at the above reduced temperature. This issue is important because it affects the compatibility of this fabrication approach with the need to obtain a high throughput in industrial electronic device processing. The results clearly demonstrate that both the SiO<sub>2</sub> and Si<sub>3</sub>N<sub>4</sub> films grown at these low temperatures (400?C) exhibited comparable growth rates to those of films thermally grown by conventional techniques at elevated temperatures (800?C-1000?C). Data is presented of Silicon Oxide (SiO<sub>2</sub>) films grown with various inert gases (He, Ar, Kr, Xe), mixed with O<sub>2</sub>. Silicon Nitride (Si<sub>3- - </sub>N<sub>4</sub>) films were grown by using Ar/N<sub>2</sub>, Ar/N<sub>2</sub>/H<sub>2</sub>, and Ar/NH<sub>3</sub> gas mixtures. Both film types were grown in a vacuum chamber using different partial and total pressures of the above gases. Plasma excitation of these gases was achieved by irradiating them with microwave frequencies of 2.45 or 8.3 GHz. MOS transistors were fabricated using gate oxide grown by the above plasma system, in order to demonstrate the system's compatibility with electronic device fabrication.
    IEEE Transactions on Semiconductor Manufacturing 06/2010; DOI:10.1109/TSM.2010.2045582 · 0.98 Impact Factor
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    ABSTRACT: Low temperature (300 °C) deposition of thin microcrystalline/amorphous silicon films by using newly developed single shower, dual injection, microwave excited high density plasma (1011 cm-3) system is described. This is an original setup based on an experimental modification of a dual shower system that was reported by us earlier. For the first time, for this system, experimental results are presented correlating between the deposition and plasma parameters with the resulting Si films atomic structure. The results consistent interdependence enables to pre-determine, in a wide range, by design, the growth of microcrystalline or amorphous thin Si films, by setting the proper deposition conditions for each film type.
    Japanese Journal of Applied Physics 04/2007; 46:2542-2553. DOI:10.1143/JJAP.46.2542 · 1.06 Impact Factor
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    ABSTRACT: In this paper, we report on an increase in emission intensity of up to 10 nW/mum2 that has been realized with a new novel two junction, diagonal avalanche control, and minority carrier injection silicon complementary metal-oxide-semiconductor (CMOS) light emitting device (LED). The device utilizes a four-terminal configuration with two embedded shallow n+p junctions in a p substrate. One junction is kept in deep-avalanche and light-emitting mode, while the other junction is forward biased and minority carrier electrons are injected into the avalanching junction. The device has been realized using standard 0.35 mum CMOS design rules and fabrication technology and operates at 9 V in the current range 0.1-3 mA. The optical output power is about one order of magnitude higher for previous single-junction n+p light-emitting devices while the emission intensity is about two orders of magnitude higher than for single-junction devices. The optical output is about three orders of magnitude higher than the low-frequency detectivity limit of silicon p-i-n detectors of comparable dimensions. The realized characteristics may enable diverse optoelectronic applications in standard-CMOS-silicon-technology-based integrated circuitry.
    Japanese Journal of Applied Physics 04/2007; 46. DOI:10.1143/JJAP.46.2474 · 1.06 Impact Factor
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    ABSTRACT: We report on an increase in emission intensity of up to 10 nW / µm 2 that has been realized with a new novel two junction, diagonal avalanche control and minority carrier injection silicon CMOS light emitting device. The device utilizes a four terminal configuration with two shallow n + p junctions, embedded in a p substrate. One junction is kept in deep avalanche and light emitting mode, while the other junction is forward biased and minority carrier electrons are injected into the avalanching junction. The device has been realized using standard 0.35 µm CMOS design rules and fabrication technology and operates at 9V in the current range 0.1 – 3mA. The optical emission intensity is anout two orders higher than that for previous single junction n + p light emitting junctions. The optical output is about three orders higher than the low frequency detectivity limit of silicon p-i-n detectors of comparable dimensions. The realized characteristics may enable diverse opto-electronic applications in standard CMOS silicon technology based integrated circuitry.
    Proceedings of SPIE - The International Society for Optical Engineering 03/2007; DOI:10.1117/12.702292 · 0.20 Impact Factor
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    ABSTRACT: A dependency of quantum efficiency of nn<sup>+</sup>pp<sup>+</sup> silicon complementary metal-oxide-semiconductor integrated light-emitting devices on the current density through the active device areas is demonstrated. It was observed that an increase in current density from 1.6×10<sup>+2</sup> to 2.2×10<sup>+4</sup> A·cm<sup>-2</sup> through the active regions of silicon n<sup>+</sup>pp<sup>+</sup> light-emitting diodes results in an increase in the external quantum efficiency from 1.6×10<sup>-7</sup> to 5.8×10<sup>-6</sup> (approximately two orders of magnitude). The light intensity correspondingly increase from 10<sup>-6</sup> to 10<sup>-1</sup> W·cm<sup>-2</sup>·mA (approximately five orders of magnitude). In our study, the highest efficiency device operate in the p-n junction reverse bias avalanche mode and utilize current density increase by means of vertical and lateral electrical field confinement at a wedge-shaped n<sup>+</sup> tip placed in a region of lower doping density and opposite highly conductive p<sup>+</sup> regions.
    IEEE Photonics Technology Letters 10/2005; 17(10):2041-2043. DOI:10.1109/LPT.2005.856448 · 2.18 Impact Factor
  • M. du Plessis, L.W. Snyman, H. Aharoni
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    ABSTRACT: Low-voltage Si-LED operation can be achieved by fabricating devices with heavily doped n<sup>+</sup>p<sup>+</sup>junctions. Differences are observed between high-voltage avalanche and low-voltage field emission LED performance. The low-voltage devices exhibit a non-linear light intensity L vs. reverse current I relationship at low current levels, but a linear dependency at higher currents, compared to the linear behavior of avalanche devices at all current levels. Three regions of operation are identified for the low-voltage field emission LED's, namely L ∝ I<sup>3</sup> at low currents, L ∝ I<sup>2</sup> at medium currents and eventually L ∝ 1 at higher currents. In the low-voltage non-linear region of operation, the shape of the emitted spectrum changes with reverse current. At low reverse current the field emission devices emit more long wavelength radiation than short wavelength radiation. As the reverse current increases, the short wavelength radiation increases relative to the long wavelength radiation, and at higher currents in the linear region of operation the ratio between long and short wavelength radiation remains constant.
    Industrial Electronics, 2005. ISIE 2005. Proceedings of the IEEE International Symposium on; 07/2005
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    L.W. Snyman, M. du Plessis, H. Aharoni
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    ABSTRACT: We report on the dependency of quantum efficiency of an avalanching silicon n<sup>+</sup>p light emitting junction on current density and on the injection current from an adjacent lying forward biased pn junction. The phenomenon was observed in a three terminal silicon bipolar junction CMOS light emitting device (Si BJ CMOS LED). The total increase in power and quantum conversion efficiency is about three orders of magnitude when compared to earlier published results. The optical emissions are about four orders higher than the low frequency detectivity for silicon CMOS detectors of comparable dimension. Because of its small spot size fabrication capability (1 micron diameter), high speed capability (up to 1 GHz), the devices have numerous potential applications in future CMOS integrated circuitry, hybrid micro-systems and MOEMS.
    Industrial Electronics, 2005. ISIE 2005. Proceedings of the IEEE International Symposium on; 07/2005
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    ABSTRACT: In this paper we report on the dependency of quantum efficiency of an avalanching light emitting junction on current density and on the injection current from an adjacent lying forward biased junction. In particular, we report on the interpretation of results and modelling of the physical processes responsible for the light emission. The phenomenon was observed in a three terminal silicon bipolar junction CMOS light emitting device (Si BJ CMOS LED). Our observations show that the overall quantum efficiency and light emission from these type of devices can be improved to the 10 -3 regime. The optical emissions is about four orders higher than the low frequency detectivity for silicon CMOS detectors of comparable dimension. The three terminal device also enable modulation of the light emission by a third terminal contact. The device has the potential of being fully integratable with standard CMOS integrated circuitry with no adaptation to the CMOS design and processing procedures.
    Proceedings of SPIE - The International Society for Optical Engineering 03/2005; DOI:10.1117/12.590553 · 0.20 Impact Factor
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    ABSTRACT: Silicon is an indirect bandgap material, but light emission is observed from reverse biased pn junctions. Even though the quantum efficiency is low, it may still be advantageous to use these devices in all-silicon optoelectronic integrated circuits (OICs). In this paper new research results with regard to low-voltage field emission BiCMOS and CMOS two- and multi-terminal Si LEDs are presented. The differences observed between avalanche and low-voltage field emission LED performance are presented. It is shown that the low-voltage devices exhibit a square-law light intensity vs. reverse current non-linearity at low-current levels, but a linear dependency at higher currents, compared to the linear behaviour of avalanche devices at all current levels. The detail spectral characteristics of the field emission devices are investigated, showing that in the non-linear region of operation, the shape of the emitted spectrum changes, with reduced short wavelength generation at lower current levels. Bipolar junction transistor (BJT) multi-terminal devices are also discussed, and the square-law behaviour of these devices is presented.
    Optical Materials 02/2005; DOI:10.1016/j.optmat.2004.08.063 · 2.08 Impact Factor
  • M. Plessis, H. Aharoni, L.W. Snyman
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    ABSTRACT: Low-voltage Si-LED operation can be achieved by fabricating devices with heavily doped n<sup>+</sup>p<sup>+</sup> junctions. Differences are observed between high-voltage avalanche and low-voltage field emission LED performance. The low-voltage devices exhibit a non-linear light intensity L vs. reverse current I relationship at low current levels, but a linear dependency at higher currents, compared to the linear behavior of avalanche devices at all current levels. Three regions of operation are identified for the low-voltage field emission LED's, namely L prop I<sup>3</sup> at low currents, L prop I<sup>2 </sup> at medium currents and eventually L prop I at higher currents. In the low-voltage non-linear region of operation, the shape of the emitted spectrum changes with reverse current. At low reverse current the field emission devices emit more long wavelength radiation than short wavelength radiation. As the reverse current increases, the short wavelength radiation increases relative to the long wavelength radiation, and at higher currents in the linear region of operation the ratio between long and short wavelength radiation remains constant
    Optoelectronic and Microelectronic Materials and Devices, 2004 Conference on; 01/2005
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    ABSTRACT: In this paper we report on the dependency of quantum efficiency of an avalanching light emitting junction on the current from an adjacent lying forward biased junction. The phenomenon is observed in a three terminal silicon CMOS bipolar junction light emitting device (Si CMOS BJT LED). Our observations show that the overall quantum efficiency and light emission from these type of devices can be improved to the N<sub>Q</sub>=10<sup>-4</sup> regime. The device has the potential of being fully integratable with any standard CMOS integrated circuitry with no adaptation to the CMOS design and processing procedures and light emissions can be confined to submicron dimensions. The optical emissions is about four orders higher than the low frequency detectivity for silicon CMOS detectors of comparable dimension. Our two junction, three terminal device also enable modulation of the light emission by a third terminal contact while using two terminals for biasing. The reverse bias avalanche configuration of the avalanching light emitting junction offers modulation capabilities of the device to within the GHz range.
    Electron Devices for Microwave and Optoelectronic Applications, 2004. EDMO 2004. 12th International Symposium on; 12/2004
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    ABSTRACT: A drastic reduction of the growth temperature of oxynitride (SiON) films, which are usually grown around 1000°C, is realized by using a microwave-excited high-density Kr-O<sub>2</sub>-NH<sub>3</sub> plasma system, which enables their growth at 400°C. It is shown that the addition of only a minute amount of nitrogen (0.5% NH<sub>3</sub> partial pressure) into a growing SiO<sub>2</sub> film, in this system, results in a significant improvements in the performance of both thick (7nm) films, which operate in the Fowler-Nordheim tunneling regime, and thin (3 nm) films which operate in the direct tunneling regime.
    IEEE Transactions on Plasma Science 09/2004; DOI:10.1109/TPS.2004.833385 · 0.95 Impact Factor
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    ABSTRACT: Although silicon is an indirect bandgap material, light emission from reverse biased pn junctions has been observed. Although the quantum efficiency is low, it will be very advantageous to utilise these devices in all-silicon optoelectronic integrated circuits (OIC's). In this paper a review of our large area display and fibre-optic devices is given, followed by new research results achieved at CEFIM with regard to low voltage two-terminal line source Si LED's. A discussion of the differences observed between avalanche and field emission LED performance is presented. The detail spectral characteristics of field emission devices, and the spectral modulation of the optical signal from field emission light emitting devices are investigated. The design and simulation of a CMOS two-colour detector is presented, to be used as a detector for spectrally modulated optical signals. Gate-controlled diode MOS-like and carrier injection BJT-like multi-terminal devices are reviewed, and it is particularly indicated that both spatial modulation of the light emitting pattern and light intensity modulation can be achieved with these devices. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
    physica status solidi (a) 08/2004; 201(10):2225 - 2233. DOI:10.1002/pssa.200404846 · 1.21 Impact Factor
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    ABSTRACT: A prototype Silicon CMOS Optical Integrated Circuit (Si CMOS OEIC) was designed and simulated using standard 0.8 micron Bi-CMOS silicon integrated circuit technology. The circuit consisted of an integrated silicon light emitting source, an optical wave-guiding structure, two integrated optical detectors and two high-gain CMOS transimpedance analogue amplifiers. Simulations with MicroSim PSpice software predict a utilizable bandwidth capability of up to 220 MHz for the trans-impedance amplifier for detected photo-currents at the input of the amplifier in the range of 1 nA to 100 nA and driving a 10mV to 1 V signal into a 100 kOmega load. First iteration OEIC structures were realised in 1.2 micron CMOS technology for various source-waveguide-detector arrangements. Current signal ranging from 1nA to 1 micro-amp was detected at detectors. The technology seems favorable for first-iteration implementation for digital communications on chip up to 200Mbps.
    Proceedings of SPIE - The International Society for Optical Engineering 07/2004; DOI:10.1117/12.530733 · 0.20 Impact Factor
  • H. Aharoni, M. du Plessis
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    ABSTRACT: A solution is presented for the fabrication of low-voltage, low-power (<4.25 V and <5 mW) silicon light-emitting devices (Si-LEDs), utilizing standard very large scale integration technology without any adaptation. Accordingly, they can be integrated with their signal processing CMOS and BiCMOS circuits on the same chip. This enables the fabrication of much needed all-silicon monolithic optoelectronic systems operated by a single supply. The structural details of two distinctly different line-patterned Si-LEDs are presented, composed of heavily doped n<sup>+</sup>p<sup>+</sup> junctions, made by BiCMOS n<sup>+</sup> sinker and PMOS p<sup>+</sup> source/drain doped regions, respectively. Using this approach, other Si-LED structures can be designed to yield low- or high-voltage Si-LED operation as well. Light is emitted at low reverse bias as a result of quantum transitions of carriers, generated by field emission, as indicated by the low reverse breakdown voltage V<sub>B</sub>, the soft "knee" I-V characteristics and the negative temperature coefficient of V<sub>B</sub>. The optical performance data show that, at low reverse operating current I<sub>R</sub>, the overall emitted light intensity L is a nonlinear function of I<sub>R</sub> and becomes linear at higher I<sub>R</sub>. A bell-shaped light spectrum is obtained, with an enhanced short wavelength and attenuated long-wavelength radiation, relative to that of avalanche Si-LEDs.
    IEEE Journal of Quantum Electronics 06/2004; 40(5-40):557 - 563. DOI:10.1109/JQE.2004.826445 · 2.11 Impact Factor
  • L.W. Snyman, H. Aharoni, M. du Plessis
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    ABSTRACT: A remarkable increase in the quantum efficiency and light emission intensity has been observed as a function of the current density for n<sup>+</sup>pp<sup>+</sup> silicon integrated light emitting devices which were fabricated with standard silicon CMOS technology. An increase of about two orders of magnitude for the quantum efficiency from 1.6 × 10<sup>-7</sup> to 5.8 × 10<sup>-6</sup> for current densities ranging from 1.6 × 10<sup>+2</sup> to 2.2 × 10<sup>+4</sup> A.cm<sup>-2</sup> is observed. The highest efficiency devices operate in the pn reverse breakdown avalanche breakdown mode and utilize current density increase by means of electrical field density confinement at a wedge shaped n<sup>+</sup> tip placed in a region of lower doping density opposite a highly conductive region. A best external quantum conversion efficiency of 5.8 × 10<sup>-6</sup> and light emission intensity of 0.1W per cm<sup>2</sup> were recorded at a current density level of 2.2 × 10<sup>+4</sup> at only 80 μm total current and 8V operating condition. This corresponds to a light intensity emission intensity of approximately 1nW in a 1 × 1 micron confined area on chip.
    Electron Devices for Microwave and Optoelectronic Applications, 2003. EDMO 2003. The 11th IEEE International Symposium on; 12/2003
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    ABSTRACT: It is demonstrated that the dependence of the reverse breakdown voltage (V<sub>B</sub>) on the ambient temperature (T) of modern shallow and ultra-shallow Si pn junctions, required for future ULSI scaled down devices, is drastically changed, with respect to that of the deeper, conventional Si pn junctions reported so far. In this work it is shown that unlike the conventional junctions in which the dV<sub>B</sub>/dT sign was determined by the dopant concentrations, in the present ultrashallow Si junctions, dVB/dT cm have positive, negative and zero slopes, in the same junction, almost independent of the dopant concentration.
    Electrical and Electronics Engineers in Israel, 2002. The 22nd Convention of; 01/2003
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    ABSTRACT: A number of planar silicon light-emitting devices are designed and realized in standard 1.2 and 2-1-mum complementary metal oxide semiconductor (CMOS) integrated circuitry. The devices yield optical power intensities of up to 0.2 muW/cm(2) (up to 0.2 nW per 100 mum(2)) at operating voltages from 4 to 31 V and at currents of 0.1 to 10 mA, respectively. The devices emit light in a broad spectrum from 450 to 800 nm with characteristic peaks at 500 and 650 nm. The emitted intensity of the devices is three to four orders of magnitude higher than the low-frequency detectability limit of integrated Si optical pn detectors utilizing similar areas on chip as the light sources. Initial investigations indicate that the devices have a very fast inherent modulation bandwidth capability. The devices show potential for on-chip electro-optical communication and chip-to-chip electro-optical communications. (C) 2002 Society of Photo-Optical Instrumentation Engineers.
    Optical Engineering 01/2003; 42(10):3059-. DOI:10.1117/1.1612927 · 0.96 Impact Factor
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    ABSTRACT: A prototype silicon CMOS optical integrated circuit (Si CMOS OEIC) was designed and simulated using standard 0.8 μm Bi-CMOS silicon integrated circuit technology. The circuit consisted of an integrated silicon light emitting source, an optical wave-guiding structure, two integrated optical detectors and two high-gain CMOS trans-impedance based analogue amplifiers. Simulations with MicroSim PSpice software predict a typical mean bandwidth capability of 185 MHz for the trans-impedance amplifier for detected photo-currents at the input of the amplifier in the range of 1 nA to 100 nA and driving a 10 kΩ load. First iteration waveguiding structures were realised in 1.2 μm CMOS technology for various source-waveguide-detector arrangements. Signal coupling ranging from 1 nA to 1 μA was detected at the detectors. The technology seems favourable for first-iteration implementations as diverse opto-electronic applications in silicon - CMOS integrated circuitry.
    Electron Devices for Microwave and Optoelectronic Applications, 2002. EDMO 2002. The 10th IEEE International Symposium on; 12/2002
  • M. du Plessis, H. Aharoni, L.W. Snyman
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    ABSTRACT: It is shown that, by using conventional VLSI design rules and device processing, a variety of two terminal and multiterminal integrated silicon light-emitting devices (Si-LEDs) can be routinely fabricated without any adaptation to the process, enabling the production of all-silicon monolithic optoelectronic systems. Their specific performance can be tailored by their different geometries and structures, yielding, by design, area, line, and point light-emitting patterns. The light-generating mechanisms are based on carrier quantum transitions in Si pn junctions, operated in the field emission or avalanche modes. Field emission Si-LEDs can operate at supply voltages compatible with those of integrated circuits (5 V or less). Avalanche Si-LEDs require higher operating voltages, but yield higher light intensities. The two terminal Si-LEDs yield a linear relation between the emitted light intensity and the driving current. The multiterminal Si-LEDs exhibit a nonlinear relation between the light emission intensity and the controlling electrical signal, enabling signal processing operations, which can not be attained in two terminal Si-LEDs. Two basic structures of multi terminal Si-LEDs are presented, i.e MOS-like structures, or carrier injection based structures (BJT-like devices). They possess different input impedances and both their emitted light intensities and emitting area patterns can be controlled by the input electrical signal.
    IEEE Journal of Selected Topics in Quantum Electronics 12/2002; DOI:10.1109/JSTQE.2002.806697 · 3.47 Impact Factor

Publication Stats

368 Citations
43.22 Total Impact Points

Institutions

  • 1996–2007
    • Ben-Gurion University of the Negev
      • Department of Electrical and Computer Engineering
      Beersheba, Southern District, Israel
  • 2004–2005
    • Tshwane University of Technology
      • Department of Electrical Engineering
      Pretoria, Gauteng, South Africa
  • 1999–2005
    • University of Pretoria
      • Department of Electrical, Electronic and Computer Engineering
      Pretoria, Gauteng, South Africa
  • 1996–2004
    • Tohoku University
      • • Department of Electronic Engineering
      • • New Industry Creation Hatchery Center
      • • Research Institute of Electrical Communication
      Sendai, Kagoshima-ken, Japan