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Abe, Shinichiro; Sato, Tatsuhiko
Journal of Nuclear Science and Technology, 53(3), p.451 - 458, 2016/03
Times Cited Count：10 Percentile：64.39(Nuclear Science & Technology)Secondary cosmic-ray neutron-induced soft errors have been recognized as a serious problem affecting the reliability of microelectronic devices. Our developed Multi-scale Monte Carlo simulator called PHYSERD is a reliable code for analysis of soft error. However, PHYSERD takes long computational time to calculate processes of collecting charges because event-by-event technology computer-aided design (TCAD) simulation is time consuming. In this study, the multiple sensitive volume (MSV) model is adopted to estimate collected charge. Secondary cosmic-ray neutron-induced soft errors in an NMOSFET are analyzed based on the MSV model using PHITS. The results are compared with those obtained by PHYSERD based on event-by-event TCAD simulation and by single sensitive volume (SSV) model using PHITS. It is found that PHITS+MSV provides approximate SERs in a shorter time than PHYSERD. Furthermore, PHITS+MSV reproduces SERs and collected charges more accurately than PHITS+SSV by considering the spatial dependence of the charge collection efficiencies.
Sato, Shinichiro; Schmieder, K. J.*; Hubbard, S. M.*; Forbes, D. V.*; Warner, J. H.*; Oshima, Takeshi; Walters, R. J.*
Proceedings of 42nd IEEE Photovoltaic Specialists Conference (PVSC-42) (CD-ROM), 5 Pages, 2015/06
GaAs pn-junction diodes with embedded InAs quantum dots (QDs) are irradiated with protons and the generated deep level traps are investigated using Deep Level Transient Spectroscopy (DLTS). The results are compared to GaAs pn-junction diodes without QDs in order to identify the origin of the deep level traps. The fluence dependence of trap density is investigated, and it is shown that majority carrier traps induced by irradiation increase in proportion to the fluence whereas the EL2 trap, which appears before irradiation, is not affected by irradiation. In addition, minority carrier traps in the QD layer and electron/hole emission from QD levels are investigated by various reverse bias and pulse voltage conditions.
Kamiya, Tomihiro; *; Tanaka, Ryuichi
Proc. of the lst Meeting on the Ion Engineering Society of Japan, p.105 - 110, 1992/00
no abstracts in English
Abe, Shinichiro; Sato, Tatsuhiko; Ogawa, Tatsuhiko
no journal, ,
In this study, we have analyzed the impact of the new version of event generator mode (e-mode ver. 2) implemented in PHITS code on evaluations of neutron-induced single event upset (SEU) for semiconductor devices. Single event effect is one of the radiation effects on the semiconductor device. The data stored in the device are flipped by the noise charge created by radiation (so-called SEU), and temporary malfunction is happened in the microelectronic device (so-called soft error). Since neutrons have no charge, they create the noise charge via a nuclear reaction. Therefore the accuracy of the nuclear reaction model is important for validating SEU cross section by simulation. The improvement of e-mode ver. 2 has been validated by comparing the product cross sections of secondary ions with those stored in the JENDL-4.0. From the comparison of SEU cross sections by e-mode ver. 2 with those obtained by e-mode ver. 1 (existing version), it is found that the improvement of e-mode have an impact on the SEU analysis.
n diodes embedded with InAs quantum dot layersSato, Shinichiro; Schmieder, K.*; Hubbard, S.*; Forbes, D.*; Warner, J.*; Oshima, Takeshi; Walters, R.*
no journal, ,
III-V semiconductor devices embedded with quantum dots (QDs) are expected to be applied to next generation space solar cells. High density QDs and highly stacked QD layers without stacking fault are required in order to relaize QD solar cells, and have been obtained recently by using strain compensating technology. However, larger amount of defects are still incorporated into QD devices compared to single crystal devices and affect the device characteristics. In this study, we fabricated GaAs pn diode with 10 layers of InAs QDs by Metal Organic Vapor Phase Epitaxy (MOVPE) method and characterized defect levels in the devices using Deel Level Transient Spectroscopy (DLTS). The results were compared to reference samples which were GaAs pn diodes without InAs QDs. It was shown that unique electron and hole trap levels were found in the QD devices and thus we concluded that these traps should be reduced in order to improve the device quality.
Abe, Shinichiro; Sato, Tatsuhiko; Kato, Takashi*; Matsuyama, Hideya*
no journal, ,
Radiation-induced charges in semiconductor device cause temporary and non-destructive faults (the so-called soft errors) in microelectronic devices. The model which estimates charges collected in the storage node of a memory element quickly and accurately is necessary to evaluate soft error rate by simulation. It is predicted that charge collection process in FinFET is differs from that in planar process due to differences in their structures. In this study, we perform systematic investigation of charge collection caused by radiation using 3-D TCAD simulator HyENEXSS in order to construct the charge collection model for FinFET. As a result of that investigation, it is found that temporal conduction between source node and drain node arises at few psec. It is also clarified that the temporal conduction has a major impact on charge collection process when charges deposited only near fin. Meanwhile, it is found that diffusion process is the main cause of charge collection when charges deposited in the substrate.
Abe, Shinichiro; Sato, Tatsuhiko; Kato, Takashi*; Matsuyama, Hideya*
no journal, ,
Radiation-induced charges in semiconductor device cause temporary and non-destructive faults (the so-called soft errors) in microelectronic devices. The model which estimates charges collected in the storage node of a memory element quickly and accurately is necessary to evaluate soft error rate by simulation. In our previous study, it was found that charge collection efficiency in FinFET change with the position and the amount of deposited charge. In this study, we construct the multiple sensitive volume model to estimate collected charge for FinFET. We obtained arbitrary charge deposition events by PHITS and analyzed charge collection of these events for by 3-D TCAD simulator HyENEXSS, the simple sensitive volume model and the multiple sensitive volume model. From the comparisons of the collected charges, it is found that the accuracy of collected charge calculation is improved by considering the variations of charge collection efficiency accompanying the position and the amount of deposited charge.
