Impacts of gate bias and its variation on gamma-ray irradiation resistance of SiC MOSFETs

Murata, Koichi; Mitomo, Satoshi; Matsuda, Takuma; Yokoseki, Takashi; Makino, Takahiro; Onoda, Shinobu; Takeyama, Akinori; Ohshima, Takeshi; Okubo, Shuichi; Tanaka, Yūki; Kandori, Mikio; Yoshie, Toru; Hijikata, Yasuto

doi:10.1002/pssa.201600446

Cited by 36 publications

(19 citation statements)

References 25 publications

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“…Therefore, more research interests are turned to the irradiation effect of the nitrided MOS capacitors and power MOSFETs. The previous studies focused on the total dose radiation response of γ-ray and X-ray, which are only considered as ionization effect [3][4][5][6][7][8][9][10]. The negative shift of V FB and threshold voltage (V TH ) is the major problem due to the positive charges generated in the gate oxide during irradiation, but the mechanisms of formation of positive charges are required to be further studied.…”

Section: Introductionmentioning

confidence: 99%

Effects of 5 MeV Proton Irradiation on Nitrided SiO2/4H-SiC MOS Capacitors and the Related Mechanisms

Zhang

Tang

et al. 2020

Nanomaterials

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In this paper the effects of 5 MeV proton irradiation on nitrided SiO2/4H-SiC metal–oxide–semiconductor (MOS) capacitors are studied in detail and the related mechanisms are revealed. The density of interface states (Dit) is increased with the irradiation doses, and the annealing response suggests that the worse of Dit is mainly caused by displacement effect of proton irradiation. However, the X-rays photoelectron spectroscopy (XPS) measurement shows that the quantity proportion of breaking of Si≡N induced by displacement is only 8%, which means that the numbers of near interface electron traps (NIETs) and near interface hole traps (NIHTs) are not significantly changed by the displacement effect. The measurements of bidirectional high frequency (HF) C-V characteristics and positive bias stress stability show that the number of un-trapped NIETs and oxide electron traps decreased with increasing irradiation doses because they are filled by electrons resulted from the ionization effect of proton irradiation, benefiting to the field effective mobility (μFE) and threshold voltage stability of metal–oxide–semiconductor field-effect transistors (MOSFETs). The obviously negative shift of flat-band voltage (VFB) resulted from the dominant NIHTs induced by nitrogen passivation capture more holes produced by ionization effect, which has been revealed by the experimental samples with different nitrogen content under same irradiation dose.

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Section: Introductionmentioning

confidence: 99%

Effects of 5 MeV Proton Irradiation on Nitrided SiO2/4H-SiC MOS Capacitors and the Related Mechanisms

Zhang

Tang

et al. 2020

Nanomaterials

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“…In particular, for the decommissioning of Tokyo Electric Power Company Holdings (TEPCO) Fukushima Dai-ichi nuclear plants, although operations of robots or sensors under high radioactive circumstance are required [1,2,3], commercial Si devices seem to be susceptible to radiation damage in such harsh conditions [4,5]. Recently, the radiation response of commercially available or prototype SiC MOSFETs against gamma ray irradiation was studied by several authors [6,7,8,9,10,11,12]. These MOSFETs have a channel length shorter than 1 μm and width on the order of a meter to conduct large currents.…”

Section: Introductionmentioning

confidence: 99%

“…These characteristics of commercial or prototype SiC MOSFETs might make their electrical properties be more sensitive to irradiation compared with ones for the basic research. So far, the radiation response was studied in terms of device structure and fabrication process [6], irradiation conditions, such as high temperature and humidity [7,8,10], and application of gate bias [11,12]. In particular, applying the positive gate bias during irradiation, the threshold voltage ( V th ) remarkably shifts in the negative direction, as reported for irradiation of positively biased Si MOSFETs [13,14,15].…”

Section: Introductionmentioning

confidence: 99%

Radiation Response of Negative Gate Biased SiC MOSFETs

et al. 2019

Self Cite

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Silicon carbide (SiC) metal-oxide-semiconductor field effect transistors (MOSFETs) are expected as power electronic devices for high radiative conditions, including nuclear plants and space. Radiation response of commercial-grade prototype SiC MOSFETs with applying the gate bias is of interest, in terms of installation of the device in robots or sensors working under such radioactive circumstances. Due to gamma-rays irradiation, the threshold voltages (Vth) of samples with un- and negative-biased up to −4.5 V slightly shift toward the negative voltage side. In contrast, the positive bias of 2.25 V shifts Vth more negatively. Positive charge densities trapped in the gate oxide of un- and positive-biased samples increased with increasing dose. However, no significant increase was observed for negative-biased samples of −2.25 and −4.5 V. We calculated characteristic parameters for the accumulation of holes in the gate oxide, σpJp which is defined as the product of current density due to holes generated by irradiation and capture cross section for a hole in a trap, and it is lower for these negative biased samples compared with the unbiased case. Application of appropriate negative gate biases to SiC MOSFETs during irradiation suppresses accumulation of positive charges in the gate oxide and negative shift of Vth, due to irradiation.

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“…Akturk et al detailed that SiC MOSFETs irradiated with gamma-rays under gate voltage biasing condition showed the negative voltage shift in threshold voltage (Vth),though in their examinations the aggregate measurement of gamma-ray dose level was limited to kGy [12]. The investigation of threshold voltage shift and drain current degradation was conducted for both N-channel and P-channel Si MOSFET subjected to electron beam radiation and gamma ray irradiation [13], [14]. However, it is necessary to consider the dynamic electrical characteristics on power MOSFETs during the total ionizing radiation.…”

Section: Introductionmentioning

confidence: 99%

Impact of gamma-ray irradiation on dynamic characteristics of Si and SiC power MOSFETs

Kannan

Krishnamurthy

Kiong

et al. 2019

IJECE

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Power electronic devices in spacecraft and military applications requires high radiation tolerant. The semiconductor devices face the issue of device degradation due to their sensitivity to radiation. Power MOSFET is one of the primary components of these power electronic devices because of its capabilities of fast switching speed and low power consumption. These abilities are challenged by ionizing radiation which damages the devices by inducing charge built-up in the sensitive oxide layer of power MOSFET. Radiations degrade the oxides in a power MOSFET through Total Ionization Dose effect mechanism that creates defects by generation of excessive electron–hole pairs causing electrical characteristics shifts. This study investigates the impact of gamma ray irradiation on dynamic characteristics of silicon and silicon carbide power MOSFET. The switching speed is limit at the higher doses due to the increase capacitance in power MOSFETs. Thus, the power circuit may operate improper due to the switching speed has changed by increasing or decreasing capacitances in power MOSFETs. These defects are obtained due to the penetration of Cobalt60 gamma ray dose level from 50krad to 600krad. The irradiated devices were evaluated through its shifts in the capacitance-voltage characteristics, results were analyzed and plotted for the both silicon and silicon carbide power MOSFET.

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Impacts of gate bias and its variation on gamma-ray irradiation resistance of SiC MOSFETs

Cited by 36 publications

References 25 publications

Effects of 5 MeV Proton Irradiation on Nitrided SiO2/4H-SiC MOS Capacitors and the Related Mechanisms

Effects of 5 MeV Proton Irradiation on Nitrided SiO2/4H-SiC MOS Capacitors and the Related Mechanisms

Radiation Response of Negative Gate Biased SiC MOSFETs

Impact of gamma-ray irradiation on dynamic characteristics of Si and SiC power MOSFETs

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