Effect of Electron Irradiation on 1700V 4H-SiC MOSFET Characteristics

2016 ◽  
Vol 858 ◽  
pp. 856-859 ◽  
Author(s):  
Stanislav Popelka ◽  
Pavel Hazdra
Keyword(s):  
Electron Irradiation ◽  
Threshold Voltage ◽  
Low Dose ◽  
Dose Range ◽  
Drift Region ◽  
Static Characteristics ◽  
Electron Dose ◽  
Deep Acceptor ◽  
Power Mosfets ◽  
Final Failure

The effect of 4.5 MeV electron irradiation on static characteristics of commercially available 5 A/1700 V SiC power MOSFETs is investigated. Results show that in the low dose range (up to 20 kGy) the threshold voltage decreases rapidly with irradiation dose but devices keep full functionality. This effect is caused by embedding of the positive charge into the gate oxide. When electron dose reaches 200 kGy, the threshold voltage moves back close to its original value, however, the ON‑state resistivity increases and transconductance is lowered. This is caused by introduction of deep acceptor centers into the low doped drift region of MOSFET. This effect can be considered as a cause of the final failure of the device (the lost of the ON-state capability).

Impact of Device Structure on Neutron-Induced Single-Event Effect in SiC MOSFETs

2019 ◽  
Vol 963 ◽  
pp. 738-741
Author(s):  
Hiroshi Kono ◽  
Teruyuki Ohashi ◽  
Takao Noda ◽  
Kenya Sano
Keyword(s):  
Threshold Voltage ◽  
Drift Region ◽  
Single Event ◽  
Drain Voltage ◽  
Device Structure ◽  
Pin Diodes ◽  
Power Mosfets ◽  
Single Event Effect ◽  
Significant Difference ◽  
Avalanche Breakdown Voltage

Neutron single event effect (SEE) tolerance of SiC power MOSFETs with different drift region design were evaluated. The SEE is detected over the SEE threshold voltage (VSEE). The failure rate increases exponentially as the drain voltage increases above VSEE. The device with higher avalanche breakdown voltage has higher SEE threshold voltage. The neutron SEE tolerance of MOSFETs and PiN diodes of the same epitaxial structure were also evaluated. There was no significant difference in the neutron SEE tolerance of these devices.

Estimation of the noise in TEM image recorded on “imaging plate”

1987 ◽  
Vol 45 ◽  
pp. 748-749
Author(s):  
T. Oikawa ◽  
N. Mori ◽  
T. Katoh ◽  
Y. Harada ◽  
J. Miyahara ◽  
...  
Keyword(s):  
Low Dose ◽  
Quantum Noise ◽  
Laser Light ◽  
Imaging Plate ◽  
Total System ◽  
Electron Dose ◽  
X Ray ◽  
Image Recording ◽  
Recording Material ◽  
Highly Sensitive

The “Imaging Plate”(IP) is a highly sensitive image recording plate for X-ray radiography. It has been ascertained that the IP has superior properties and high practicability as an image recording material in a TEM. The sensitivity, one of the properties, is about 3 orders higher than that of conventional photo film. The IP is expected to be applied to low dose techniques. In this paper, an estimation of the quantum noise on the TEM image which appears in case of low electron dose on the IP is reported.In this experiment, the JEM-2000FX TEM and an IP having the same size as photo film were used.Figure 1 shows the schematic diagram of the total system including the TEM used in this experiment. In the reader, He-Ne laser light is scanned across the IP, then blue light is emitted from the IP.

Critical Technical Issues in High Voltage SiC Power Devices

2008 ◽  
Vol 600-603 ◽  
pp. 895-900 ◽  
Author(s):  
Anant K. Agarwal ◽  
Albert A. Burk ◽  
Robert Callanan ◽  
Craig Capell ◽  
Mrinal K. Das ◽  
...  
Keyword(s):  
Threshold Voltage ◽  
Carrier Mobility ◽  
Negative Charge ◽  
State Of The Art ◽  
Power Devices ◽  
Power Mosfets ◽  
Large Numbers ◽  
Technical Issues ◽  
The Difference ◽  
Difficult Issue

In this paper, we review the state of the art of SiC switches and the technical issues which remain. Specifically, we will review the progress and remaining challenges associated with SiC power MOSFETs and BJTs. The most difficult issue when fabricating MOSFETs has been an excessive variation in threshold voltage from batch to batch. This difficulty arises due to the fact that the threshold voltage is determined by the difference between two large numbers, namely, a large fixed oxide charge and a large negative charge in the interface traps. There may also be some significant charge captured in the bulk traps in SiC and SiO2. The effect of recombination-induced stacking faults (SFs) on majority carrier mobility has been confirmed with 10 kV Merged PN Schottky (MPS) diodes and MOSFETs. The same SFs have been found to be responsible for degradation of BJTs.

scholarly journals Skin regeneration is accelerated by a lower dose of multipotent mesenchymal stromal/stem cells—a paradigm change

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gertraud Eylert ◽  
Reinhard Dolp ◽  
Alexandra Parousis ◽  
Richard Cheng ◽  
Christopher Auger ◽  
...  
Keyword(s):  
Stem Cells ◽  
Wound Healing ◽  
Low Dose ◽  
Dose Range ◽  
High Dose ◽  
Full Thickness ◽  
Burn Wound ◽  
Dermal Regeneration Template ◽  
Yorkshire Pigs ◽  
Stromal Stem Cells

Abstract Background Multipotent mesenchymal stromal/stem cell (MSC) therapy is under investigation in promising (pre-)clinical trials for wound healing, which is crucial for survival; however, the optimal cell dosage remains unknown. The aim was to investigate the efficacy of different low-to-high MSC dosages incorporated in a biodegradable collagen-based dermal regeneration template (DRT) Integra®. Methods We conducted a porcine study (N = 8 Yorkshire pigs) and seeded between 200 and 2,000,000 cells/cm2 of umbilical cord mesenchymal stromal/stem cells on the DRT and grafted it onto full-thickness burn excised wounds. On day 28, comparisons were made between the different low-to-high cell dose groups, the acellular control, a burn wound, and healthy skin. Result We found that the low dose range between 200 and 40,000 cells/cm2 regenerates the full-thickness burn excised wounds most efficaciously, followed by the middle dose range of 200,000–400,000 cells/cm2 and a high dose of 2,000,000 cells/cm2. The low dose of 40,000 cells/cm2 accelerated reepithelialization, reduced scarring, regenerated epidermal thickness superiorly, enhanced neovascularization, reduced fibrosis, and reduced type 1 and type 2 macrophages compared to other cell dosages and the acellular control. Conclusion This regenerative cell therapy study using MSCs shows efficacy toward a low dose, which changes the paradigm that more cells lead to better wound healing outcome.

scholarly journals DETERMINATION OF ELECTRON BEAM CHARGING CONDITIONS OF OXIDES AT LOW ENERGY IN THE LOW DOSE RANGE

1989 ◽  
Vol 50 (C6) ◽  
pp. C6-174-C6-174
Author(s):  
M. VALENZA ◽  
P. GIRARD ◽  
B. PISTOULET
Keyword(s):  
Electron Beam ◽  
Low Dose ◽  
Dose Range ◽  
Low Energy

scholarly journals SUN-042 Low Dose Cyproterone Acetate for the Treatment of Transgender Women - a Retrospective Study

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Naomi Even-Zohar ◽  
Yael Sofer ◽  
Iris Yaish ◽  
Merav Serebro ◽  
Karen Tordjman ◽  
...  
Keyword(s):  
Cyproterone Acetate ◽  
Dose Group ◽  
Low Dose ◽  
Dose Range ◽  
Hormonal Treatment ◽  
Transgender Women ◽  
High Dose ◽  
Historical Cohort ◽  
Treatment Groups ◽  
First Time

Abstract Introduction : Transgender women with intact gonads receive lifelong hormonal treatment in order to suppress physiologic androgen production. Cyproterone acetate (CA) is the most comon antiandrogenic drug prescribed for this indication in Europe, with a dose range between 25-100 mg/day. Aim: To assess the effectiveness and safety of low dose (<20 mg/day), compared with high dose (>50 mg/day) CA treatment. Methods: Historical cohort study of transgender women treated in our department between January 2000 and October 2018. Results: There were 42 transgender women in the low dose group (LDG) and 32 in the high dose group (HDG). Age (27.9 ± 1.6 vs.28.9 ± 1.7 years) and follow up time (16.2 ± 2.2 vs. 20.1 ± 2.1 months) were similar in the LDG and HDG, respectively. At the last available visit, testosterone levels were effectively and similarly suppressed in both treatment groups (0.6 ± 0.1 vs 0.8 ± 0.3 nmol/l; p=0.37, for LDG and HDG respectively). Prolactin (659 ± 64 vs 486 ± 42 mIU/ml, p=0.02), LDL cholesterol (96.1 ± 5 vs 78.5 ± 4 mg/dl, p= 0.02) and triglycerides (93.3 ± 9 vs 69 ± 5 mg/dl; p=0.02) were higher in the HDG compared with LDG respectively. Side effects were common in the HDG (four cases of increased liver enzymes, one case of pulmonary embolism and one case of sudden death). Conclusion: We show for the first time that anti-androgenic treatment of transgender women with low dose CA is as effective as high dose treatment, but safer. We suggest incorporation of this observation in future guidelines.

scholarly journals First Insights into the Effect of Low-Dose X-Ray Irradiation in Adipose-Derived Stem Cells

2019 ◽  
Vol 20 (23) ◽  
pp. 6075 ◽  
Author(s):  
Annemarie Schröder ◽  
Stephan Kriesen ◽  
Guido Hildebrandt ◽  
Katrin Manda
Keyword(s):  
Stem Cells ◽  
Low Dose ◽  
Dose Range ◽  
Adipose Derived Stem Cells ◽  
Long Term Effects ◽  
Low Dose Radiation ◽  
Term Survival ◽  
Cell Therapies ◽  
Dose Radiation

(1) Background: Emerging interest of physicians to use adipose-derived stem cells (ADSCs) for regenerative therapies and the fact that low-dose irradiation (LD-IR ≤ 0.1 Gy) has been reported to enhance the proliferation of several human normal and bone-marrow stem cells, but not that of tumor cells, lead to the idea of improving stem cell therapies via low-dose radiation. Therefore, the aim of this study was to investigate unwanted side effects, as well as proliferation-stimulating mechanisms of LD-IR on ADSCs. (2) Methods: To avoid donor specific effects, ADSCs isolated from mamma reductions of 10 donors were pooled and used for the radiobiological analysis. The clonogenic survival assay was used to classify the long-term effects of low-dose radiation in ADSCs. Afterwards, cytotoxicity and genotoxicity, as well as the effect of irradiation on proliferation of ADSCs were investigated. (3) Results: LD (≤ 0.1 Gy) of ionizing radiation promoted the proliferation and survival of ADSCs. Within this dose range neither geno- nor cytotoxic effects were detectable. In contrast, greater doses within the dose range of >0.1–2.0 Gy induced residual double-strand breaks and reduced the long-term survival, as well as the proliferation rate of ADSCs. (4) Conclusions: Our data suggest that ADSCs are resistant to LD-IR. Furthermore, LD-IR could be a possible mediator to improve approaches of stem cells in the field of regenerative medicine.

scholarly journals Lack of Efficacy of Propofol in the Treatment of Early Postoperative Nausea and Vomiting

1998 ◽  
Vol 26 (4) ◽  
pp. 366-370 ◽  
Author(s):  
I. Harper ◽  
E. Della-Marta ◽  
H. Owen ◽  
J. Plummer ◽  
A. Ilsley
Keyword(s):  
Low Dose ◽  
Dose Range ◽  
Postoperative Nausea And Vomiting ◽  
Nausea And Vomiting ◽  
Test Drug ◽  
Gynaecological Surgery ◽  
Treatment Groups ◽  
Sedation Scores ◽  
To Receive ◽  
Rescue Antiemetic

The anti-nauseant efficacy of low-dose propofol was investigated in a blinded, randomized trial. Patients who complained of nausea and/or vomiting following laparoscopic gynaecological surgery and who requested antiemetic were randomly assigned to receive placebo, propofol 3 mg, propofol 9 mg or propofol 27 mg by intravenous injection. Nausea, vomiting and sedation were recorded by a blinded observer for 90 minutes following administration of the test drug, prior to discharge, and 24 hours following surgery. Rescue antiemetic (droperidol 1.0 mg IV) was available from 10 minutes after administration of test drug. Propofol failed to reduce nausea scores and did not reduce the incidence of vomiting. Numbers of patients receiving rescue antiemetic were similar in the four treatment groups. In the first 10 minutes following test drug administration, sedation scores were increased by propofol in a dose-related manner. We conclude that, in the dose range studied, propofol is ineffective for the treatment of nausea and vomiting occurring soon after laparoscopic gynaecological surgery.

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