Physics and Innovative Technologies in SiC Power Devices

Kimoto, Tsunenobu; Kaneko, Mitsuaki; Tachiki, Keita; Itō, Kōji; Ishikawa, Ryoya; Chi, Xilun; Stefanakis, Dionysios; Kobayashi, Takuma; Tanaka, Hiromu

doi:10.1109/iedm19574.2021.9720696

Cited by 12 publications

(7 citation statements)

References 15 publications

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“…[3][4][5][6] Just like Si MOSFETs, numerous studies link the electrical characteristic changes of the devices before and after irradiation to the radiation-induced interface traps and oxide traps. [7][8][9][10] Meanwhile, since 4H-SiC MOS-FETs have long suffered from poor interface quality, [11][12][13] nitric oxide (NO) or nitrous oxide (N 2 O) post-annealing has been utilized in the production of commercial 4H-SiC MOS-FETs to suppress the interface trap density. [14][15][16] However, many studies suggest that interface nitridation not only passivates the intrinsic defects but also introduces additional interface and/or near-interface oxide traps as well, [17] making the trapping mechanism in 4H-SiC MOSFETs more complex and significantly different from that of Si MOSFETs.…”

Section: Introductionmentioning

confidence: 99%

Impact of low-dose radiation on nitrided lateral 4H-SiC MOSFETs and the related mechanisms

Zhang

Zhu

et al. 2023

Chinese Phys. B

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Lateral type n-channel 4H-SiC MOSFETs fabricated by current industrial process are irradiated with gamma-ray at different irradiation doses in this paper, to make a profound study on the generation mechanism of radiation-induced interface traps and oxide trapped charges. Electrical parameters (e.g. threshold voltage, subthreshold swing and channel mobility) of the device before and after irradiation are investigated, and the influence of the channel orientation ([1$\bar 1$00] and [11$\bar 2$0]) on the radiation effect is discussed for the first time. Positive threshold voltage shift is observed at very low irradiation doses (<100 krad(Si)), the threshold voltage then shifts negatively with dose increasing. It is found that the dependence of interface trap generation on radiation dose is not the same for doses below and above 100 krad. For irradiation doses <100 krad, the radiation-induced interface traps with relatively high generation speeds dominate the competition with radiation-induced oxide trapped charges, contributing to the positive threshold voltage shift correspondingly. All these results provide additional insight into the radiation-induced charge trapping mechanism in SiO2/SiC interface.

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Section: Introductionmentioning

confidence: 99%

Impact of low-dose radiation on nitrided lateral 4H-SiC MOSFETs and the related mechanisms

Zhang

Zhu

et al. 2023

Chinese Phys. B

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“…On the other hand, in this study, the channel was formed on 1100 ( ¯)-face which inversion electron flowed along [0001] and electron mobility was enhanced by tensile stress opposite to the results of the former investigations. [20][21][22] However, it was reported that 4H-SiC has anisotropy of some electrical characteristics such as Hall electron mobility 35) and impact ionization coefficient for electrons [36][37][38] due to its unique and unclear conduction band structure 39) and the anisotropy depends on the direction of electron flow. Therefore, it can be thought that the result of this study implies that the relationship between stress and electron mobility also has anisotropy which depends on the direction of channel and inversion electron flow.…”

Section: Discussionmentioning

confidence: 99%

Enhancement of channel mobility in 4H-SiC trench MOSFET by inducing stress at SiO₂/SiC gate interface

Kagoshima¹,

Takeuchi²,

Kutsuki³

et al. 2022

Jpn. J. Appl. Phys.

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To investigate the impact of stress at the SiO2/SiC gate interface on the channel mobility of 4H-SiC trench MOSFETs, we fabricated trench MOSFETs with two variations of stress in channel region by changing the deposition temperature of polycrystalline silicon used for gate electrodes. The results found that effective mobility was enhanced by several dozen MPa of tensile stress induced by the polycrystalline silicon. Based on the temperature dependence of mobility, all scattering mobilities were enhanced. It was supposed that the electron effective mass decreased because of tensile stress induced at the channel region.

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“…Silicon carbide (SiC) single crystal materials, as third-generation semiconductor materials, have larger bandgap widths, higher critical breakdown electric field strengths, better thermal conductivity, high saturated electron migration rates, good voltage withstanding ability, and extremely low conduction energy losses [1,2]. The bandgap width of SiC can reach 3.2 eV, three times that of Si [3,4].…”

Section: Introductionmentioning

confidence: 99%

Improvement of microtubule defects of SiC substrate through a thermal effect control method

Shen,

Li,

Yeh

et al. 2024

Fifth International Conference on Optoelectronic Science and Materials (ICOSM 2023)

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Silicon carbide, as a third-generation semiconductor, has numerous advantages, such as high-pressure resistance, hightemperature resistance, high-frequency and high-power capabilities, radiation resistance, etc. Due to these properties, it is widely used in the fields of high-power transmission devices and new energy. However, the problem of microtubules needs urgent attention. During the crystal growth process, thermal stress generates microtubules, which results in the formation of hollow screw dislocations with a large Burgess vector, leading to a particular hollow structure. Microtubules greatly affect the performance and lifespan of the device under high voltage and high current conditions. In this paper, we have significantly improved the microtubule defects issue by controlling the thermal field. The diameter of a single microtubule was reduced from 10 μm to 1 μm, and the density of microtubules decreased from 3.98 to 0.8 microtubules/cm². As a result, the quality of silicon carbide crystals has been significantly enhanced.

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Physics and Innovative Technologies in SiC Power Devices

Cited by 12 publications

References 15 publications

Impact of low-dose radiation on nitrided lateral 4H-SiC MOSFETs and the related mechanisms

Impact of low-dose radiation on nitrided lateral 4H-SiC MOSFETs and the related mechanisms

Enhancement of channel mobility in 4H-SiC trench MOSFET by inducing stress at SiO₂/SiC gate interface

Improvement of microtubule defects of SiC substrate through a thermal effect control method

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Physics and Innovative Technologies in SiC Power Devices

Cited by 12 publications

References 15 publications

Impact of low-dose radiation on nitrided lateral 4H-SiC MOSFETs and the related mechanisms

Impact of low-dose radiation on nitrided lateral 4H-SiC MOSFETs and the related mechanisms

Enhancement of channel mobility in 4H-SiC trench MOSFET by inducing stress at SiO2/SiC gate interface

Improvement of microtubule defects of SiC substrate through a thermal effect control method

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Enhancement of channel mobility in 4H-SiC trench MOSFET by inducing stress at SiO₂/SiC gate interface