Investigation of Forward Voltage Degradation due to Process-Induced Defects in 4H-SiC MOSFET

2018 ◽  
Vol 924 ◽  
pp. 365-368 ◽  
Author(s):  
Kumiko Konishi ◽  
Ryusei Fujita ◽  
Yuki Mori ◽  
Akio Shima
Keyword(s):  
High Reliability ◽  
Stress Test ◽  
Implantation Dose ◽  
Imaging Method ◽  
Stress Tests ◽  
Forward Voltage ◽  
Current Stress ◽  
Before And After ◽  
Induced Defects ◽  
Voltage Degradation

We investigated process induced defects at various ion implantation conditions, and evaluated forward voltage degradation of body diode in 3.3 kV SiC MOSFET. First, by using photoluminescence (PL) observation, we evaluated the formation level of Basal Plane Dislocations (BPD) induced by Al implantation and anneal process with various Al implantation dose. Second, 3.3 kV double-diffused SiC MOSFETs were fabricated and forward current stress tests were performed to body diodes in SiC MOSFETs. Then, electrical characteristics of SiC MOSFETs before and after the stress test were measured, and expanded Stacking faults (SFs) in SiC epitaxial layer after the stress test were observed by PL imaging method. These results indicate that low dose or high temperature Al implantation conditions can suppress the formation of BPDs, and SiC MOSFETs fabricated using optimized Al implantation conditions show high reliability under current stress test.

Dynamic Characteristics of 4H-SiC pin Diode on (000-1)C-Face with Small Forward Degradation

2006 ◽  
Vol 527-529 ◽  
pp. 1359-1362 ◽  
Author(s):  
Koji Nakayama ◽  
Yoshitaka Sugawara ◽  
R. Ishii ◽  
Hidekazu Tsuchida ◽  
Toshiyuki Miyanagi ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Stress Test ◽  
Pin Diode ◽  
Forward Voltage ◽  
Current Stress ◽  
Before And After ◽  
Voltage Degradation ◽  
A Current

Forward voltage degradation has been reduced by fabricating diodes on the (000-1)C-face. The reverse recovery characteristics of the 4H-SiC pin diode on the (000-1)C-face have been investigated. The pin diode on the C-face has superior potential to that on the Si-face among all parameters of the reverse recovery characteristics. The pin diode on the Si-face after conducting a current stress test tends to exhibit a fast turn-off as compared with that before conducting the stress test. On the C-face, however, there is little difference in reverse recovery characteristics between before and after conducting the current stress test.

A 300°C High Reliability HALT/HAST Screening/Sorting Procedure for Ceramic Capacitors

2018 ◽  
Vol 2018 (HiTEC) ◽  
pp. 000129-000137 ◽  
Author(s):  
Harold L. Snyder
Keyword(s):  
High Reliability ◽  
Stress Test ◽  
Electrical Current ◽  
Accelerated Life Test ◽  
Test Results ◽  
Electrical Model ◽  
Current Leakage ◽  
Ceramic Capacitor ◽  
Ceramic Capacitors ◽  
Before And After

Abstract A highly accelerated life test (HALT) and highly accelerated stress test (HAST) procedure for ceramic capacitors developed by the author in the mid 1980's to early 1990's, and published in 1994, consists of a 400 Volt biased six (6) hour stress sort at 150°C (423K), a methanol current leakage test that located mechanical and structural cracks, a visual inspection at ten times (10×) magnification, and a capacitance and dissipation measurement before and after the test. In over thirty (30) years of use, there has never been a user reported in-circuit failure in industrial, military, and aerospace application at temperatures as high as 500°C (773K). However, reviewing user feedback, two concerns with the original sorting procedure are the stress is performed at 150°C (423K), and the lack of a more detailed ceramic capacitor electrical model. To address the first, the low aging temperature, the stress temperature was increased from 150°C to 300°C, in order to age ceramic solid state crystal mineral phases that may change with temperature. The test results for X7R and NP0/COG multilayer ceramic capacitors (MLCC) at 300°C, are compared to the test results using the original HALT/HAST procedure at 150°C. Differences between X7R/NP0/COG and porcelain capacitors are discussed when applicable. Further, a more detailed ceramic capacitor electrical model that represents the physical and electrical characteristics of the ceramic capacitors is presented, including the electrical current leakage effects with temperature, and the carbonized residue effects from the manufacturing process.

Exercise performance in children and adolescents after the Ross procedure

2006 ◽  
Vol 16 (1) ◽  
pp. 40-47 ◽  
Author(s):  
Bradley S. Marino ◽  
Sara K. Pasquali ◽  
Gil Wernovsky ◽  
John R. Bockoven ◽  
Michael McBride ◽  
...  
Keyword(s):  
Children And Adolescents ◽  
Exercise Performance ◽  
Stress Test ◽  
Ideal Body Weight ◽  
Exercise Stress Test ◽  
Exercise Stress ◽  
Ross Procedure ◽  
Stress Tests ◽  
Primary Indication ◽  
Before And After

Objectives:The Ross procedure is increasingly utilized in the treatment of aortic valvar disease in children and adolescents. Our purpose was to compare pre- and post-operative exercise state in this population.Methods:We included patients who underwent the Ross procedure at our institution between January, 1995, and December, 2003, and in whom we had performed pre- and post-operative exercise stress tests. We used a ramp bicycle protocol to measure consumption of oxygen and production of carbon dioxide. Cardiac output was estimated from effective pulmonary blood flow by the helium acetylene re-breathing technique.Results:We studied 26 patients, having a median age at surgery of 15.7 years, with a range from 7.5 to 24.1 years. The primary indication for surgery in two-thirds was combined aortic stenosis and insufficiency. Median time from the operation to the post-operative exercise stress test was 17.4 months, with a range from 6.7 to 30.2 months. There was a trend toward lower maximal consumption of oxygen after the procedure, at 36.3 plus or minus 7.6 millilitres per kilogram per minute (83.9% predicted) as opposed to 38.6 plus or minus 8.4 millilitres per kilogram per minute (88.5% predicted, p equal to 0.06). Patients after the procedure, however, had significantly increased adiposity, so that there was no difference in maximal consumption of oxygen indexed to ideal body weight before and after the operation. In 20 of the patients, aerobic capacity improved or was stable after the operation. There was no post-operative chronotropic impairment.Conclusions:In the majority of patients following the Ross procedure, exercise performance is stable and within the normal range of a healthy age and sex matched population, despite sedentary lifestyles and increased adiposity.

Modeling of Stacking Fault Expansion Velocity of Body Diode in 4H-SiC MOSFET

2017 ◽  
Vol 897 ◽  
pp. 214-217 ◽  
Author(s):  
Kumiko Konishi ◽  
Ryusei Fujita ◽  
Akio Shima ◽  
Yasuhiro Shimamoto
Keyword(s):  
Electrical Measurement ◽  
Stacking Fault ◽  
Junction Temperature ◽  
Expansion Velocity ◽  
Forward Voltage ◽  
Forward Current ◽  
Before And After ◽  
Voltage Degradation ◽  
Good Agreement

We present a model to explain forward voltage degradation of body diode in 4H-SiC MOSFET, and evaluate the velocity of SF expansion. First, by using in-situ photoluminescence (PL) observation, we investigated how a stacking fault (SF) expands from a basal plane dislocations (BPD) in the 4H-SiC epitaxial layer. Second, double-diffused MOSFETs were developed and measured before and after degradation. Then, the characteristics of the forward voltage degradation were modeled by a combination of PL imaging and electrical measurement, and the calculated characteristics are in good agreement with the measured ones. Finally, we tested the SiC MOSFETs under various stress conditions and evaluated the velocity of the SF expansion by calculation. This results indicate that the velocity of SF expansion increased with increasing forward current density and junction temperature.

scholarly journals Protective Effect of Microbubble Aeration and Dietary Probiotics BALSS on Survival and Immunity of White Leg Shrimp (Litopenaeus vannamei) Postlarvae against Acute Low Salinity Stress

2020 ◽  
Vol 22 (1) ◽  
pp. 1
Author(s):  
Shima Bhaskara Ayuningrum ◽  
Indah Istiqomah ◽  
Rustadi Rustadi ◽  
Bambang Triyatmo ◽  
Alim Isnansetyo ◽  
...  
Keyword(s):  
Survival Rate ◽  
Glucose Level ◽  
Salinity Stress ◽  
Bactericidal Activity ◽  
Litopenaeus Vannamei ◽  
Stress Test ◽  
Stress Tests ◽  
Low Salinity ◽  
Before And After ◽  
Experimental Trials

Survival rate and immunity of white leg shrimp ((Litopenaeus vannamei) postlarvae against acute salinity stress were evaluated in indoor experimental trials. The research was conducted with 2x2 factorial design with two levels of aeration (microbubble and macro bubble) and two levels of diet (with and without probiotics) resulting four treatments in triplicate: application of microbubble with gut probiotics (MiP), without gut probiotics (MiC), and macro bubble with gut probiotics (MaP) and without probiotics (MaC). White leg shrimps measuring 7.6 g were maintained in the tanks for 60 days and fed five times a day at a dose of 5% biomass. Harvested shrimp were tested for low salinity stress (5 ppt) for 3 hours. Glucose level, total protein, bactericidal activity, natural agglutination, phenoloxidase, respiratory burst, and superoxide dismutase activities in the hemolymph and the shrimp survival rate (SR) were analyzed before and after the stress tests. Although all examined parameters remained the same between groups before the stress test, significant differences were found among them after the stress test. Microbubble aeration obtained stabilization of hemolymph glucose level, best survival rate, bactericidal activity, and agglutination activities. No significant effect was resulted by the dietary probiotic treatments, but the interaction with aeration treatments revealed the importance to compensate shrimp survival rate when microbubble aeration is unavailable.

A 300°C High Reliability HALT/HAST Screening/Sorting Procedure for Ceramic Capacitors – Part 2

2021 ◽  
Vol 2021 (HiTEC) ◽  
pp. 000094-000099
Author(s):  
Harold L. Snyder
Keyword(s):  
High Reliability ◽  
Stress Test ◽  
Electrical Current ◽  
Accelerated Life Test ◽  
Test Results ◽  
Electrical Model ◽  
Current Leakage ◽  
Ceramic Capacitor ◽  
Ceramic Capacitors ◽  
Before And After

Abstract This is Part 2 of a study initially presented at HiTEC 2018, for context, some introductory material is duplicated. A highly accelerated life test (HALT) and highly accelerated stress test (HAST) procedure for ceramic capacitors developed by the author in the mid 1980’s to early 1990’s, and published in 1994, consists of a 400 Volt biased six (6) hour stress sort at 150°C (423K), a methanol current leakage test that located mechanical and structural cracks, a visual inspection at ten times (10X) magnification, and a capacitance and dissipation measurement before and after the test. In over thirty (30) years of use, there has never been a user reported in-circuit failure in industrial, military, and aerospace application at temperatures as high as 500°C (773K). However, reviewing user feedback, two concerns with the original sorting procedure are the stress is performed at 150°C (423K), and the lack of a more detailed ceramic capacitor electrical model. To address the first, the low aging temperature, the stress temperature was increased from 150°C to 300°C, in order to age ceramic solid state crystal mineral phases that may change with temperature. The test results for X7R and NP0/COG multilayer ceramic capacitors (MLCC) at 300°C, are compared to the test results using the original HALT/HAST procedure at 150°C. Differences between X7R/NP0/COG and porcelain capacitors are discussed when applicable. Further, a more detailed ceramic capacitor electrical model that represents the physical and electrical characteristics of the ceramic capacitors is presented, including the electrical current leakage effects with temperature, and the carbonized residue effects from the manufacturing process.

Stress Test of Cascode Switch Using SiC Static Induction Transistor

2020 ◽  
Vol 1004 ◽  
pp. 985-991
Author(s):  
Takashi Matsumoto ◽  
Yasunori Tanaka ◽  
Koji Yano
Keyword(s):  
High Reliability ◽  
Stress Test ◽  
Drain Current ◽  
Electrical Characteristics ◽  
Stress Tests ◽  
Turn On ◽  
Significant Difference ◽  
Static Induction Transistor ◽  
Static Induction ◽  
Channel Region

Stress tests were conducted for the cascode switch using the SiC buried gate static induction transistor (SiC-BGSIT). The stress of the reverse overshoot voltage was periodically applied to the pn junction between the gate terminal and source one in the BGSIT in the cascode with pulses of 40kHz for 202 hours. This simulates the stress which can be occurred in the channel region of the BGSIT during the turn-off and turn-on operation with a parasitic inductance in the interconnection of the cascode package. The result of the stress tests has revealed that there is no significant difference between the electrical characteristics of the BGSIT cascode sample before the stress and those after the stress. Thus, the BGSIT cascode can guarantee high reliability against the stress. The result from the drain current DLTS suggests that no deferent kind of defect is created in the channel region of the BGSIT by the stress.

Quality Control of Composite Material Pipes by Infrared Thermography

2012 ◽  
Vol 188 ◽  
pp. 140-143 ◽  
Author(s):  
Alexandrina Mihai ◽  
Florin Ştefănescu ◽  
Gigel Neagu ◽  
C.P. Mihai
Keyword(s):  
Infrared Thermography ◽  
Oil And Gas ◽  
High Reliability ◽  
Stress Test ◽  
Oil And Gas Industry ◽  
Gas Industry ◽  
Before And After ◽  
Reference Images ◽  
Composite Pipes ◽  
The Impact

The paper presents some aspects concerning the use of infrared thermography (IRT) in the evaluation of composite pipes integrity. Composite pipelines made up of glass fibres reinforced epoxy resins are increasingly used, especially in oil and gas industry, for their good mechanical properties, combined with reduced weight and excellent behaviour under hostile environment conditions. Taking into account that high reliability is required for such pipe networks, it is mandatory to choose reliable non-destructive inspection (NDI) methods to achieve efficient structural health monitoring. The main advantages of the IRT inspection are: non-contact and non-dangerous examination. In order to characterize the integrity of composites pipes, first of all the researches were interested in obtaining a set of reference images and then to examine the samples before and after the impact stress test. The conclusions point out the schemes and the optimal parameters of evaluation as well as the application limits of thermographic inspection

scholarly journals Cardiovascular Autonomic Response to Amlodipine in Primary Hypertension

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Youssouf Radjab ◽  
Souad Aboudrar ◽  
Fatima Zahra Milouk ◽  
Hanan Rkain ◽  
Mustapha EL Bakkali ◽  
...  
Keyword(s):  
Oral Administration ◽  
Mental Stress ◽  
Stress Test ◽  
Primary Hypertension ◽  
Autonomic Response ◽  
Vagal Activity ◽  
Deep Breathing ◽  
Stress Tests ◽  
Hand Grip ◽  
Before And After

Sympathetic hyperactivity may be involved in primary hypertension. The purpose of this study was to evaluate both sympathetic and vagal activity responses in patients receiving amlodipine as antihypertensive agent. Patients and Methods. This prospective study included a group of primary hypertensive patients (N=32, mean age 54.6±7.6 years). The cardiovascular autonomic tests performed in this group, before and after 3 months of daily oral administration of amlodipine, included deep breathing, hand-grip, and mental stress tests. Statistical analysis was done using the Student’s t-test. Results. Cardiovascular autonomic reflexes responses before and after 3 months of amlodipine oral administration were as follows: the mental stress test stimulation method produced a central alpha adrenergic response of 23.9±8.7% versus 11.2±2.0% (P<0.05), a central beta sympathetic response of 16.7±9.2% versus 10.4±1.3% (P<0.05), a blood pressure increase in response to hand grip test of 20.5±7.3% versus 10.7±2.4% (P<0.05), vagal response to deep breathing test was 21.2±6.5% versus 30.8±2.9%, (P<0.05). Conclusion. The results attest that amlodipine may have an anti-sympathetic effect.

scholarly journals Advanced Electrical Characterisation of High Voltage 4H-SiC PiN Diodes

2019 ◽  
Vol 963 ◽  
pp. 567-571 ◽  
Author(s):  
Besar Asllani ◽  
Dominique Planson ◽  
Pascal Bevilacqua ◽  
Jean Baptiste Fonder ◽  
Beverley Choucoutou ◽  
...  
Keyword(s):  
Breakdown Voltage ◽  
High Voltage ◽  
Stress Test ◽  
High Current ◽  
Stress Tests ◽  
Pin Diodes ◽  
Current Stress ◽  
Current Pulses ◽  
Switching Behaviour ◽  
Good Behaviour

This paper reports the design, the processing, the static characterisation, the switching behaviour and the high current stress test of 10 kV aimed 4H-SiC bipolar diodes. The actual breakdown voltage of the selected devices is between 7 kV and 8 kV. The switching characterisations show a good behaviour with a trr of only 90 ns. No degradation was observed after the application of 10 000 high current pulses during the stress tests.

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