森 英喜

Microscopic characterization of generation lifetimes in a SiO 2 /Si structure has been carried out using scanning capacitance microscopy (SCM). Generation lifetimes could be investigated by monitoring the capacitance transient due to inversion layer formation. The validity of local capacitance transient measurements by SCM was verified by comparing with the results of conventional capacitance transient measurements using a MOS capacitor. Furthermore, it was demonstrated that SCM can be used for imaging of the formation process of the inversion layer on a nanometer scale.

Contactless capacitance transient techniques have been applied to local mapping of interface traps of a semiconductor wafer. In contactless capacitance transient techniques, a Metal-Air gap-Oxide-Semiconductor (MAOS) structure is used instead of a conventional Metal-Oxide-Semiconductor (MOS) structure. The local mapping of interface traps was obtained by using a contactless Isothermal Capacitance Transient Spectroscopy (ICTS), which is one of the contactless capacitance transient techniques. The validity of the contactless ICTS was demonstrated by characterizing a partially Au-doped Si wafer. The results revealed that local mapping of interface traps using contactless capacitance transient techniques is effective in wafer inspection and is a promising technique for the development of MOS devices and solar cells with high reliability and high performance. (C) 2016 Author(s).

In recent years, special interests have been paid to the advantage of using III-V compound semiconductors for the microelectronic and optoelectronic industries because of its high-speed response. Ion beam induced charge (IBIC) and transient-IBIC techniques are useful in order to investigate the single event effects, which is one of the most serious problems to use semiconductor devices in space. During image collection, the ion-induced damage is introduced. Therefore the degradation behavior of collected charge and transient current are important issue to use these techniques most effectively. To estimate degradation behavior, the damage factors of InGaAs devices are compared with that of Si devices by using the concept of non-ionizing energy loss. © 2003 Elsevier B.V. All rights reserved.

A single-event upset (SEU) is triggered when the amount of charge induced by an energetic ion striking a sensitive area exceeds a critical charge within a given time interval. An accurate understanding of the charge collection processes that give rise to SEU is critical for the design of SEU tolerant microelectronic devices. The best method for clearly examining charge collection during an SEU is to examine the ultra-fast current transient waveform. This is best achieved by a heavy-ion microbeam in combination with an ultra-fast sampling oscilloscope. In the past there have been numerous experiments aimed at directly measuring the ultra-fast current transient induced in various diodes by single ion strikes. The aim has been to examine the effect of charge collection components such as drift, funneling and diffusion on the SEU processes. In this paper, we present a summary of various experiments using the newly developed transient ion beam induced current system developed at JAERI. © 2003 Elsevier B.V. All rights reserved.

The MeV ion and laser microbeams are the two most commonly used tools for examining the spatial and temporal dependence of charge collection processes that lead to single event phenomena in semiconductor devices. In this paper, we perform a detailed comparison of the fundamental differences that exist between the two methods for examining single event transients in InGaAs photodetectors. In particular, we compare results collected by transient laser and ion beam induced current for several ion species. (C) 2003 Elsevier B.V. All rights reserved.

It is known that the single-event phenomena (SEP) are the malfunction of micro electronics devices caused by the impact of an energetic heavy ion. Improving the tolerance of devices to the SEP requires a better understanding of basic charge collection mechanisms on the timescales of the order of picoseconds. In order to better elucidate these mechanisms, we measure the fast transient current resulting from heavy ion strikes with a fast sampling data collection system and a heavy ion microbeam line at JAERI. In this paper we report on differences in both the transient current and charge collection from 15 MeV carbon ions on silicon-on-insulator, Si epilayer and bulk p(+)n junction diodes and charge transportation under MeV ion injection is discussed. (C) 2003 Elsevier B.V. All rights reserved.

We have succeeded in measuring single-event current pulses in silicon-on-insulator (SOI) structures using collimated heavy-ion beams in conjunction with a wide-bandwidth current-pulse measurement system. The total amount of collected charges for ions incident on the p(+)n junction indicate collection from below the top silicon layer in the SOI diode. For such high energies, SOI structures were found to be an ineffective means for ensuring the radiation hardness of electronic devices used in space. (C) 2003 Elsevier Science B.V. All rights reserved.

Photonic devices operating in space must exhibit high-radiation hardness due to prolonged exposure to high-energy radiation fields. The device performance can be influenced by both the transient effect of electron-hole plasma generation due to stopping of high-energy particles, and the accumulated effect of damage introduced by a flux of particles. The complex relationship between the two is an increasingly important area of research. Here we investigate charge collection characteristics of in situ ion beam induced damaged samples by measuring single event transient currents induced by heavy ions. Results from this study suggest that the ion-induced charge degradation can be predicted for any ion species and energy using the concept of non-ionizing energy loss and displacement damage dose. (C) 2003 Elsevier Science B.V. All rights reserved.

Single MeV ion induced currents are directly responsible for a wide range of single event phenomena leading to temporary or permanent malfunction of devices in radiation environments such as space. The active regions of a device act as a source of transient currents injected into a device subsystem by collecting the charge induced by MeV ions. As such, the charge collection process is an important step in understanding mechanisms that lead to device malfunction. In this paper, we present transient current data collected on Si epilayer devices with 15 MeV O4+ ions focused using a MeV heavy ion micro-probe. The measured transient currents are compared to quasi-3D simulation using ISE TOAD software. Critical factors influencing the fidelity of the measurement technique and modeling of heavy ion track models are also discussed. (C) 2003 Elsevier Science B.V. All rights reserved.

Single-event phenomena (SEP) are common occurrences in electronic devices used in high-radiation fields such as space environments. SEP are primarily caused by the interaction between ionization tracks generated by a high-energy heavy ion and sensitive regions of a semiconductor device. In order to develop SEP tolerance devices, it is necessary to predict the amount of the collected charge at sensitive regions. In this paper, comparing the experimental results obtained from the waveform of the transient current induced by a heavy ion and from a geometrical model, we have studied the ion-induced transient charge as a function of an angle and the linear energy transfer (LET) of the incident tons. (C) 2003 Elsevier Science B.V. All rights reserved.

The optical spectral response of Si pin photodiodes was examined after gamma and electron irradiation. We observed both a significant decrease in the peak optical response and peak position with increasing total dose. This effect was successfully explained by modeling the degradation of the minority carrier diffusion length in the base region. The diffusion length damage factor was estimated in the context of the nonionization energy loss (NIEL). A close agreement was found between the observed degradation behavior and that predicted by NIEL.

We report on the temperature dependence of the heavy-ion transient-ion beam induced current response of Si epilayer devices from 80 to 300 K. The measurements were performed on a heavy-ion microbeam in conjunction with the new transient-ion beam induced current system developed at the Japan Atomic Energy Research Institute. Furthermore, we perform a detailed comparison with technology computer-aided design (TCAD) simulations and discuss the results in terms of TCAD modeling, experimental procedure, and the implications for temperature-related single-event upset modeling.

We report on the temperature dependence of the heavy ion Transient-Ion Beam Induced Current response of Si epilayer devices from 80K to 300K. The measurements were performed on a heavy ion micro-beam in conjunction with the new Transient-Ion Beam Induced Current system developed at JAERI. Furthermore, we perform a detailed comparison with TCAD simulations and discuss the results in terms of TCAD modeling, experimental procedure and the implications for temperature related SEU modeling.

For the study of basic mechanism of single-event upset, we have developed a transient current measurement system comprising a heavy-ion micro-beam combined with an ultra-fast transient acquisition system. Transient current, waveforms induced by high-energy heavy ion strikes in test structures are reported.

The optical spectral response of Si pin photodiodes was examined after gamma and electron irradiation. We observed both a significant decrease in the peak optical response and peak position with increasing total dose. This effect was successfully explained by modeling the degradation of the minority carrier diffusion length in the base region. The diffusion length damage factor was estimated in the context of the Non-Ionization Energy Loss (NIEL). A close agreement was found between the observed degradation behavior and that predicted by NIEL.

A new target chamber and control system for temperature-based transient-IBIC and transient-LBIC measurements using the same experimental chamber is outlined. The system has been designed for both ultra-fast and relatively slow transient measurements as a function of temperature from 77 K to 450 K. The control system, implemented in the Labview environment, allows single ion scanning and transient acquisition on a set of oscilloscopes, for an array of temperatures and bias. The modularity of the system allows its use for a broad range of experiments from single event upset transient current measurements to scanning ion deep level transient spectroscopy charge transient measurements. In this paper, we describe the overall system and illustrate its potential by way of example. (C) 2001 Elsevier Science B.V. All rights reserved.

Single-event upsets (SEUs) are a major concern for dynamic random access memory (DRAM) and static random access memory (SRAM) installed in space-based satellites. Recently, large-scale integration of memory devices has made them even more susceptible to multiple-bit upsets (MBUs). MBU generally results when an ion strike passes through, or interferes with, multiple memory cells at the same time. However, the fundamental processes behind MBU have not yet been fully clarified. In order to investigate the mechanism of MBU, we examined the relationship between the amount of the collected charge and the angle of the incident ion to the test device. (C) 2001 Published by Elsevier Science B.V.

We have investigated the degradation of optocoupler components, i.e., Si p(+)-i-n photodiodes and GaAlAs LEDs, under gamma and electron irradiations. The results can be explained with a decrease in the minority carrier lifetime caused by the formation of defects during irradiations. Degradation of the electrical characteristics of p(+)-i-n photodiodes was found to be significant in comparison with that of LEDs. It suggests that the degradation of p(+)-i-n photodiode becomes dominant in radiation degradation of optocoupler. (C) 2001 Published by Elsevier Science Ltd.

High-energy heavy-ion microbeams are useful for studying single-event phenomena(SEP) in semiconductor devices. However, current SEP research is concentrating on higher energies provided by cyclotrons. Focusing such high-energy beams is extremely difficult so we have taken the approach of using microcollimator to form a highly collimated beam which can then be positioned accurately on the device under test. In order to measure the beam profiles produced by such a system, we have employed a 16 Mbit DRAM (dynamic random access memory) to measure both the occurrence of a single-event upset and its spatial location. Using the DRAM method, 150 (MeVAr8+)-Ar-40 beams collimated to 100 mum have been characterized, The results indicate that high inteplated memory devices can replace a position-sensitive detector (PSD) and provide an even higher spatial resolution. (C) 2001 Published by Elsevier Science Ltd.

In this paper we detail the new Transient Ion Beam Induced Current (TIBIC) and Transient Laser Beam Induced Current (TLBIC) measurement system developed at JAERI, Takasaki. Both measurements are performed in the same chamber as a function of sample temperature. The primary purpose of the chamber and data collection system is for the detailed investigation of ultra fast charge collection processes which give rise to Single Event Phenomenon (SEP) in radiation hard environments such as space. The system caters for both ultra-fast and relatively slow transient measurements as a function of temperature from 77K to 450K. The control system, implemented in the Labview environment, allows single ion scanning and transient acquisition on a range of oscilloscopes, for an array of temperatures and biases. The modularity of the system allows its use in a broad range of experiments, ranging from Single Event Upset (SEU) Transient Current measurements to Scanning Ion Deep Level Transient Spectroscopy (SIDLTS) charge transient measurements. Here we describe the overall system and illustrate the systems potential under several markedly different experimental configurations.

The ultra-fast transient response of silicon on insulator (SOI) p(+)n devices has been investigated using an wide bandwidth measurement system developed for the high-energy heavy-ion microbeam at JAERI, Takasaki. The system can be used study Single Event Upset (SEU) processes in semiconductor devices by probing device structures with a 1 mum beam spot. In this study we briefly describe the system and report on its use for examining ultrafast charge collection dynamics in SOI structures. We show that a proper positioning of the buried oxide layer can effectively control the total charge collected in an SOI device.