Kiyoteru Hayama

Kumamoto National College of Technology · Information, Communication and Electronics Engineering

The trial production of a new concept vertical take-off and landing aircraft of tilted triple rotors attached flying wing was carried out for power saving and long flight. The 45° tilted triple rotors are fixed at a position symmetrical to the center of gravity. Stabilization during hovering and level flight could be realized by a commercially avai...

The trial production of a new concept quadcopter with a vertical-axis wind turbine (VAWT) is presented for power-saving during forward flight. Continuous transition from hovering to power-saving level flight can be done only by tilting forward of the quadcopter. The VAWT rotates with the downwash of its rotors and against the wind by forward flight...

The fixed-wing aircraft has an advantage of wide range of flight area caused by the high-speed and the energy efficiency than the rotorcraft, but it cannot hover in the air and takes a runway field to take-off and landing. In our previous research, variable pitch wing attached multicopter is developed and the lift of wing during level flight is par...

The trial production of a new concept vertical take-off and landing rotorcraft of flexible kite wing attached multicopter was carried out for power saving and long flight. The area and incident angle of the kite wing are changed in conjunction. Continuous transition from vertical to level flight can be done with automatically adjusting suitable ang...

In this paper, we propose a two-channel microphone system with variable arbitrary directional pattern for multiple sound signals. The proposed method can change the direction of unidirectional pattern and can select multiple directivity patterns. The method can reduce noise even when the number of sound sources is larger than that of observed mixtu...

The trial production of new concept vertical take-off and landing (VTOL) aircraft based on modified Y4 quadcopter was carried out for aerial, observation and research. The VTOL is made up of the reversed Y4 quadcopter with tilt mechanism of coaxial rotors and fixed-wing with elevon. Continuous transition from the rotorcraft to fixed-wing aircraft c...

Trial production has begun on tricopter-based new-concept vertical take-off and landing aircraft (VTOL). The VTOL features three fixed-angle motors on a reversed-T shape body and a fixed wing with an elevon and a rudder. The proposed craft uses fewer components than quadcopter-based VTOL craft. Continuous transition from rotorcraft to fixed-wing cr...

Though normal multirotor is difficult long flight from restriction of the capacity of power source for using batteries, long operation by wire feeding is useful in limited applications. The control of the multirotor is required enough skill. But the operation has become easier by the aid of attitude and position control using various sensors and GP...

In this study, focusing the difference between the sound powers observed by microphones is depending on the location of the sound source, we propose a method of forming a sharp directivity by three microphones. The implementation of directional characteristics by real-time processing of sounds observed by three microphones were carried out using mb...

The paper propose a real-time blind source separation method without a scaling indeterminacy. The proposed method does not require an iteration processing. The scale of separated signals using the proposed method are decided by these transfer functions. This fact means that the separated signals are expressed as the observed signals in the case whi...

In recent years, there are a lot of products of autonomous robot such as a robotic vacuum cleaner. Autonomous robot is useful as a teaching tool for learning of electronic control technology. Micromouse is well known as an autonomous mobile robot that runs to explore the maze. In this study, we have developed teaching materials micromouse with the...

In this study, focusing the difference between the sound powers observed by two microphones is depending on the location of the sound source, we propose a method of forming a sharp directivity by two microphones. The implementation of directional characteristics by real-time processing of sounds observed by two microphones were carried out using mb...

The trial production of new concept vertical take-off and landing aircraft (VTOL) based on tricopter was carried for aerial, observation and research. The VTOL is made up of the fixed angle three motors located reversed T shape, fixed wing with elevon and rudder. The proposed aircraft is made by minimum components compared with that of already publ...

The trial production of new concept rotorcraft was carried for the aiming at a weather survey. The three blades with movable wing vane and driving force are connected fixed pitch angle. The direction of flight is controllable using at least one movable wing vane which is synchronizing with rotation of the aircraft by monitoring the direction with a...

The trial production of the coaxial helicopter with fail-safe function by the rotational control was carried out for the aiming at a weather survey. The aircraft is controlled by movable wing vane which is synchronizing with aspect of the aircraft, monitoring the direction by a geomagnetism sensor. Therefore, the direction of flight of the aircraft...

Micromouse competition is one of the most famous autonomous robot competitions. Although the producing micromouse has technical difficulty, it is very useful for students to study embedded systems if the educational materials are enough prepared. Simply design and development of micromouse for embedded system education are presented.

Particle-tracking detectors made on high-resistivity (HR) float zone (FZ) silicon are widely used in high-energy physics experiments. It is known that the incorporation of oxygen in the FZ Si can lead to some improvement in the radiation hardness of the material. In this contribution we investigate the effects of 2 MeV electron irradiation, up to a...

The radiation damage induced by 2-MeV electrons and 70-MeV protons in p+n diodes and p-channel MOS transistors, fabricated in epitaxial Ge-on-Si substrates is reported for the first time. For irradiation above 5×1015 e/cm2, it is noted that both the reverse and forward current increase, and that the forward current is lower after irradiation for a...

A transparent electrode of β-Ga2O3 films for solar cells, flat panel displays and other devices, which consist in chemically abundant and ecological elements of gallium and oxygen, were grown on quartz or silicon substrates by RF magnetron sputtering using a sintered Ga2O3 target. The impurities of Si or Ge were also added into the grown films. The...

The drain current (ID) transients by switching the biasing condition are examined in FD-SOI MOSFETs with negative biased back gate voltage (VBG). Special attention is paid to the influence of the gate-induced charge/discharge of the floating body on the ID transient. The ID transient appears not only by switching the front gate voltage (VFG) but al...

Total-dose response of npn Si transistors by 2-MeV electrons is presented for different dose rates. The base current increases after irradiation, whereas the collector current decreases. Therefore, the current gain (β) decreases by irradiation. The degradation of electrical properties by 2-MeV electrons for low dose rate is higher than that for hig...

The effect of hot-carrier stress on 60 MeV proton irradiated thin gate oxide partially depleted SOI nMOSFETs has been studied. The results are compared with those from the electrical stress of non-irradiated devices. Whereas no significant differences are observed for the front channel degradation, hot-electron trapping in the buried oxide is found...

In this paper, the appearance of gate induced floating body effects in triple gate SOI nFinFETs with TiN/SiON and TiN/HfO2 gate stacks is investigated. Different floating body effects (FBEs) are found to appear under moderate accumulation back gate bias (VBG) conditions in devices with wide and long enough geometries. In particular, a second peak i...

The degradation of the electrical properties of thin gate oxide PD-SOI n-MOSFETs by 2-MeV electrons at different dose rates is presented. The degradation of the back channel and its dependence on dose rate are clarified. The characteristics of the PD-SOI MOSFETs are degraded, and the degradation becomes higher for a low dose rate. The magnitude of...

Strained Si layers (sSi) on strain-relaxed SiGe buffer layers are frequently used in order to boost up the carrier mobility. This study investigates the degradation of such sSi n-MOSFETs by 20-MeV proton irradiation. The drain current decreases and a negative shift of the threshold voltage is observed after proton irradiation. The impact of the fab...

In this study, experiment set up for engineering students is proposed. The experiment using the proopsed set up consists of the model computer, internal parts for theoretical test, external parts for input/output examination and exclusive assembler. Students try to design a logic circuit and implement the logic circuit on FPGA (field programmable g...

The hysteresis characteristics of the drain current (ID) in FD-SOI n-MOSFETs are examined at different back gate voltage and temperature. The relationship between the hysteresis and the temperature is discussed in comparison with the result for PD-SOI n-MOSFETs, taking into account the back gate interface states. The ID hysteresis, which is defined...

The impact of hot-carrier degradation on drain current (ID) hysteresis and switch-off ID transients of thin gate oxide floating body PD SOI nMOSFETs is analyzed. An extended characterization of these floating body effects (FBEs) is carried out for a wide range of transistor geometries and bias conditions. The results show a link between the hot-car...

Degradation of the electrical performance in partially depleted SOI MOSFETs by 2-MeV electrons is presented. The degradation behavior of the 2nd transconductance (gmf) peak and its dependence on the back gate voltage is discussed taking into account the degradation of the back gate. The drain current in the subthreshold region is increased by irrad...

The degradation of the electrical performance of 2-MeV electron-irradiated thin gate oxide FD-SOI MOSFETs fabricated on ELTRAN and UNIBOND wafers is reported. The difference of the degradation is examined by analyzing the extracted MOS-transistor parameters. The degradation of the performance is discussed taking into account the front-back gate cou...

Strain Silicon (sSi) layers on strain-relaxed SiGe buffer layers are frequently used in order to boost up the carrier mobility. Recently, fabrication techniques based on the use of ultra-thin (300–400 nm) SRB layers have been proposed. This study investigates the degradation of such sSi n-MOSFETs after 2-MeV electron irradiation. Owing to the elect...

The hysteresis characteristics of the drain current in PD-SOI n-MOSFETs are examined at different back gate voltages (VBG) and temperatures. The relationship between the hysteresis and the back gate interface states is also discussed. The ID hysteresis, which is defined as the difference of ID for VFG swept up and down, showed both positive (1st) a...

The degradation behavior for Si p-i-n photodiodes by neutron irradiation at different temperatures was studied. The degradation of the electrical device performance is more pronounced for low-temperature irradiations. Two electron capture levels at E-C - 0.22eV and E-C - 0.40eV, respectively, were observed by deep level transient spectroscopy. The...

The degradation of 2-MeV electron-irradiated C-doped SiGe diodes was investigated. After electron irradiation, the reverse current increases with increasing electron fluence, while the capacitance decreases. At the highest fluence studied (1×1016e/cm2), a different behaviour of the reverse current with junction area was observed. DLT spectra show t...

The degradation of deep submicrometer (0.1 μm) fully depleted silicon-on-insulator n-MOSFETs subjected to 2-MeV electron irradiation at different temperatures is reported. The radiation-induced damage is investigated by studying the static characteristics of devices with different geometries and bias conditions. The change of the front and back-cha...

The degradation of the electrical performance of 2-MeV electron-irradiated thin gate oxide FD-SOI MOSFETs fabricated on ELTRAN and UNIBOND wafers is reported. The difference of the degradation is examined by analyzing the extracted MOS-transistor parameters. The degradation of the performance is discussed taking into account the front-back gate cou...

The floating well operation of bulk MOSFETs is studied at 77 K in order to get a better insight in the underlying physics. It will be shown that a metastable threshold voltage (VT) behaviour can be induced by sweeping the linear characteristics from accumulation to inversion gate bias. Depending on the magnitude of the drain bias, a positive or neg...

The degradation of the electrical performance of thin gate oxide fully depleted SOI n-MOSFETs and its dependence on the radiation particles are investigated. The transistors are irradiated with 7.5-MeV protons and 2-MeV electrons at room temperature without bias. The shift of threshold voltage and the coupling effect with the degraded opposite gate...

A new method for body potential estimation of ultra thin gate oxide fully-depleted silicon-on-insulator MOSFETs in accumulation mode operation is presented. The impact of the back gate voltage, gate length and drain voltage on the body potential is investigated. The magnitude of the Electron Valence Band gate tunneling-induced 2nd peak of the trans...

The degradation of deep submicron (0.1 μm) fully depleted (FD)-silicon-on-insulator (SOI) n-channel metal oxide semiconductor field effect transistors (MOSFETs) subjected to 7.5-MeV proton irradiation is reported. The radiation-induced damage is investigated by studying the static characteristics of devices with different geometries and bias condit...

In this study, we analyze the impact of back-channel radiation-induced leakage and back-gate bias on switch-off drain current transients of thin-gate-oxide partially depleted (PD) silicon-on-insulator (SOI) n-channel metal-oxide-semiconductor field-effect transistors (MOSFETs). The presence of radiation-induced positive trapped charges in the burie...

The degradation of the electrical performance of ultra thin gate oxide fully depleted (FD)-SOI n-MOSFETs subjected to 7.5-MeV proton irradiation is reported. The degradation is investigated by studying the static characteristics of transistors with different geometries and back-gate bias conditions. Special attention is paid to the analysis of the...

The degradation of the electrical properties of deep submicron metal-oxide-semiconductor field-effect transistors (MOSFETs) by 2 MeV electron irradiation at high temperatures was studied. The irradiation temperatures were 30, 100, 150 and 200 °C, and the fluence was fixed at 1015 e/cm2. For most experimental conditions, the threshold voltage (VT) i...

Results are presented of a detailed study of the effects of high-temperature 2-MeV electron irradiation on the performance degradation of InGaAs photodiodes. The macroscopic device performance will be correlated with the radiation-induced defects, observed by DLTS. It was found that the dark current increases after irradiation, while the photo curr...

The impact of a 60 MeV proton irradiation on the static characteristics of 0.13 μm CMOS transistors is investigated, as a function of the device length and width. It is shown that the degradation of the threshold voltage and of the transconductance exhibits a marked length dependence, with more pronounced changes for shorter devices. From the indep...

Results are presented of a detailed study of the effects of high-temperature 2-MeV electron and 4-MeV neutron irradiation on the performance degradation of InGaAs photodiodes. The macroscopic device performance will be correlated with the radiation-induced defects, observed by DLTS. It was found that the dark current increases after irradiation, wh...

Results are presented of a study of the radiation damage by high-temperature electron irradiation in deep submicron MOSFETs. The 2-MeV electrons were irradiated onto the MOSFETs at 30, 100, 150 and 200°C for a fluence of 1015 e/cm2. Before and after irradiation, the electrical properties of the MOSFETs were measured in order to examine the effect o...