Current Gain Stability of SiC Junction Transistors Subjected to Long-Duration DC and Pulsed Current Stress

2016 ◽  
Vol 858 ◽  
pp. 929-932 ◽  
Author(s):  
Siddarth Sundaresan ◽  
Brian Grummel ◽  
Ranbir Singh
Keyword(s):  
Stress Test ◽  
Current Gain ◽  
Pulsed Current ◽  
Similar Extent ◽  
Current Stress ◽  
Current Stressing ◽  
Long Duration ◽  
Current Operation ◽  
Dc Current

The current gain stability of a second generation of 1200 V rated SiC Junction Transistors (SJTs) under long-term DC and pulsed current operation is investigated. A 1000-hour long, 200 A/cm2 DC current stress results in a ≈ 10% reduction of the current gain (β) during the early stages of the stress test, while the β is perfectly stable for the remainder (>90%) of the stress duration. The same amount of stress charge applied as a pulsed current in lieu of DC current results in similar extent of β degradation for the Gen-II SJTs. The pulsed current stressing is conducted at frequencies ranging from 50 kHz to 200 kHz, at a fixed duty cycle of 0.5.

Stability of Electrical Characteristics of SiC “Super” Junction Transistors under Long-Term DC and Pulsed Operation at various Temperatures

2012 ◽  
Vol 1433 ◽  
Author(s):  
Siddarth G. Sundaresan ◽  
Aye-Mya Soe ◽  
Ranbir Singh
Keyword(s):  
Voltage Drop ◽  
Stress Test ◽  
Base Plate ◽  
Current Gain ◽  
Common Source ◽  
Pulsed Current ◽  
Electrical Characteristics ◽  
Plate Temperature ◽  
Term Operation

ABSTRACTThe reliability of the electrical characteristics of SiC “Super” Junction Transistors (SJTs) is investigated under long-term avalanche-mode, DC and pulsed-current operation. There is absolutely no change in the blocking I-V characteristics after a 934 hour repetitive avalanche stress test. Long-term operation of the Gate-Source diode (open-Drain mode) alone does not result in any degradation of the on-state voltage drop (VF) or current gain (β). Long-term operation in common-Source mode results in negligible VF or β degradation, if the base-plate is maintained at 25 °C. A greater degradation of β results with increasing base-plate temperature. The same total electrical charge, if passed through the SJT as a pulsed current instead of a DC current results in a smaller β reduction. It is also shown that this β degradation can be reversed by annealing at ≥ 200 °C, suggesting the possibility of degradation-free operation of SiC SJTs, when operating in pulsed current mode at ≥ 200 °C temperatures.

Current Gain Degradation in 4H-SiC Power BJTs

2011 ◽  
Vol 679-680 ◽  
pp. 702-705 ◽  
Author(s):  
Benedetto Buono ◽  
Reza Ghandi ◽  
Martin Domeij ◽  
Bengt Gunnar Malm ◽  
Carl Mikael Zetterling ◽  
...  
Keyword(s):  
Stress Test ◽  
Stacking Faults ◽  
Current Gain ◽  
Electrical Measurements ◽  
Long Term Stability ◽  
Emitter Region ◽  
Collector Region ◽  
Power Application ◽  
Test Current

SiC BJTs are very attractive for high power application, but long term stability is still problematic and it could prohibit commercial production of these devices. The aim of this paper is to investigate the current gain degradation in BJTs with no significant degradation of the on-resistance. Electrical measurements and simulations have been used to characterize the behavior of the BJT during the stress test. Current gain degradation occurs, the gain drops from 58 before stress to 43 after 40 hours, and, moreover, the knee current shows fluctuations in its value during the first 20 hours. Current gain degradation has been attributed to increased interface traps or reduced lifetime in the base-emitter region or small stacking faults in the base-emitter region, while fluctuations of the knee current might be due to stacking faults in the collector region.

Rapidly Maturing SiC Junction Transistors Featuring Current Gain (β) > 130, Blocking Voltages up to 2700 V and Stable Long-Term Operation

2014 ◽  
Vol 778-780 ◽  
pp. 1001-1004 ◽  
Author(s):  
Siddarth G. Sundaresan ◽  
Stoyan Jeliazkov ◽  
Brian Grummel ◽  
Ranbir Singh
Keyword(s):  
Size Effect ◽  
High Gain ◽  
Current Gain ◽  
High Current ◽  
Current Stress ◽  
Term Operation

SiCnpnJunction Transistors (SJTs) with current gains as high as 132, low on-resistance of 4 mΩ-cm2, and minimal emitter-size effect are demonstrated with blocking voltages > 600 V. 2400 V-class SJTs feature blocking voltages as high as 2700 V combined with on-resistance as low as 5.5 mΩ-cm2. A significant improvement in the current gain stability under long-term high current stress is achieved for the SJTs fabricated by the high gain process.

Breakthrough performance, reliability and robustness of SiC Junction Transistors

MRS Advances ◽  
2016 ◽  
Vol 1 (54) ◽  
pp. 3619-3630
Author(s):  
Siddarth Sundaresan ◽  
Ranbir Singh
Keyword(s):  
Breakdown Voltage ◽  
Short Circuit ◽  
Stress Test ◽  
Negative Temperature ◽  
Current Gain ◽  
Switching Frequency ◽  
Drift Region ◽  
Collector Current ◽  
Current Stress ◽  
High Switching Frequency

ABSTRACT Despite having an npn epitaxial structure resembling a Si BJT, the switching performance of the SiC Junction Transistor or SJT is purely controlled by its terminal capacitances, similar to a SiC MOSFET or JFET. Further, the absence of a “high-resistance” SiC MOS channel in the SJT means that the SJT’s RON,sp is solely limited by the resistance of the n- drift region. Recently released SJTs feature RON,sp as low as 2 mΩ-cm2 for a breakdown voltage (BV) of 1600 V, and a RON,sp of 2.4 mΩ-cm2, for a breakdown voltage of 2000 V. Current gains > 100 are achieved, even on the highest current SJTs. Unlike Si BJTs, SJTs do not suffer from second breakdown, and can perform under unclamped inductive switching (UIS) conditions, even at full rated collector currents. Near-∞ Early voltage and a negative temperature co-efficient of current gain in a SJT ensure low collector currents under short-circuited load conditions, resulting in short-circuit withstand time as high as 14 µs, even at > 80% of the maximum rated BV. Recent technological developments have significantly improved the stability of the SJT current gain (β) under high-current stress conditions. A 1000-hour long, 200 A/cm2 DC current stress results in only 10% reduction of the current gain (β) during the early stages of the stress test, while the β is perfectly stable for the remainder (>90%) of the stress duration. Similar β compression is observed, whether the collector current stress is applied at DC, or at a high switching frequency ≥ 200 kHz.

Improvement of the Current Gain Stability of SiC Junction Transistors

2015 ◽  
Vol 821-823 ◽  
pp. 822-825 ◽  
Author(s):  
Siddarth Sundaresan ◽  
Brian Grummel ◽  
Dean Hamilton ◽  
Ranbir Singh
Keyword(s):  
Drain Current ◽  
Current Gain ◽  
Current Stress ◽  
Dc Current

SiC Junction Transistors (SJTs) with 1900 V Drain-Source breakdown voltages, current gain (hFE) higher than 120 and low on-resistance of 22 mΩ (3.5 mΩ-cm2) are reported in this paper. SJTs with a pre-stress hFE of 90 suffer only a 10% reduction of the hFE after 190 hours under a 200 A/cm2 DC current stress at a TJ of 125°C, while a similar stress on earlier generation SJTs resulted in over 25% hFE reduction in only 25 hours. SJT die with pre-stress hFE in the range of 120-125 show absolutely no current gain degradation even after a 300°C/ 2 hour stress at 60 A/cm2 DC drain current.

CHANGES IN BLOOD PROTEOME OF COSMONAUTS WITH MICRO- AND MACROVASCULAR INJURIES DUE TO G-LOADS AT THE FINAL STAGE OF LONG-DURATION SPACE MISSIONS

2020 ◽  
Vol 54 (5) ◽  
pp. 5-14
Author(s):  
L.Kh. Pastushkova ◽  
◽  
K.S. Kireev ◽  
I.M. Larina ◽  
◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Soft Tissues ◽  
Blood Rheology ◽  
Landing Site ◽  
Space Missions ◽  
Vascular Injuries ◽  
New Approach ◽  
Long Duration ◽  
Integrated Response

The integrated response of the human proteome to re-entry g-loads following long-term space missions was studied in 13 male cosmonauts at the age of 44 ± 6 years. Examination at the landing site discovered local petechial hemorrhages into soft tissues of the back and lower legs. The paper presents a new approach to evaluation of petechia and soft tissue hemorrhages in cosmonauts on return to Earth. Proteomic analysis was performed with the use of LC-MS. Bioinformation analysis was made using Perseus, PubMed, Uniprot and ANDSystem software. Nine out of 19 significantly different (p < 0.05) proteins were related to vascular injuries directly. We described proteins with a primarily protecting effect against endothelial cells apoptosis and augmentation of vascular permeability, proteins that are responsible for blood rheology and proteins antagonistic to the main triggers of ischeamia-reperfusion injuries of the lungs, liver and other parenchymal organs.

scholarly journals Long-Term Microgravity Effects on Isometric Handgrip and Precision Pinch Force with Visual and Proprioceptive Feedback

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Ilario Puglia ◽  
Michele Balsamo ◽  
Marco Vukich ◽  
Valfredo Zolesi
Keyword(s):  
Maximum Voluntary Contraction ◽  
Space Station ◽  
Voluntary Contraction ◽  
Force Output ◽  
Isometric Handgrip ◽  
Short Term ◽  
Space Flights ◽  
Pinch Force ◽  
Long Duration

The study and analysis of human physiology during short- and long-duration space flights are the most valuable approach in order to evaluate the effect of microgravity on the human body and to develop possible countermeasures in prevision of future exploratory missions and Mars expeditions. Hand performances such as force output and manipulation capacity are fundamental for astronauts’ intra- and extravehicular activities. Previous studies on upper limb conducted on astronauts during short-term missions (10 days) indicated a temporary partial reduction in the handgrip maximum voluntary contraction (MVC) followed by a prompt recovery and adaptation to weightlessness during the last days of the mission. In the present study, we report on the “Crew’s Health: Investigation on Reduced Operability” (CHIRO) protocol, developed for handgrip and pinch force investigations, performed during the six months increment 7 and increment 8 (2003-2004) onboard International Space Station (ISS). We found that handgrip and pinch force performance are reduced during long-term increments in space and are not followed by adaptation during the mission, as conversely reported during short-term increment experiments. The application of protocols developed in space will be eligible to astronauts during long-term space missions and to patients affected by muscle atrophy diseases or nervous system injury on Earth.

scholarly journals FCCSP IMC growth under reliability stress follows automotive criteria

2019 ◽  
Vol 3 (1) ◽  
pp. 70-83
Author(s):  
Wei Wei Liu ◽  
Berdy Weng ◽  
Scott Chen
Keyword(s):  
High Temperature ◽  
Flip Chip ◽  
Stress Test ◽  
Temperature Cycling ◽  
Content Type ◽  
Initial Stage ◽  
High Temperature Storage ◽  
Temperature Cycling Test ◽  
Temperature Storage

Purpose The Kirkendall void had been a well-known issue for long-term reliability of semiconductor interconnects; while even the KVs exist at the interfaces of Cu and Sn, it may still be able to pass the condition of unbias long-term reliability testing, especially for 2,000 cycles of temperature cycling test and 2,000 h of high temperature storage. A large number of KVs were observed after 200 cycles of temperature cycling test at the intermetallic Cu3Sn layer which locate between the intermetallic Cu6Sn5 and Cu layers. These kinds of voids will grow proportional with the aging time at the initial stage. This paper aims to compare various IMC thickness as a function of stress test, the Cu3Sn and Cu6Sn5 do affected seriously by heat, but Ni3Sn4 is not affected by heat or moisture. Design/methodology/approach The package is the design in the flip chip-chip scale package with bumping process and assembly. The package was put in reliability stress test that followed AEC-Q100 automotive criteria and recorded the IMC growing morphology. Findings The Cu6Sn5 intermetallic compound is the most sensitive to continuous heat which grows from 3 to 10 µm at high temperature storage 2,000 h testing, and the second is Cu3Sn IMC. Cu6Sn5 IMC will convert to Cu3Sn IMC at initial stage, and then Kirkendall void will be found at the interface of Cu and Cu3Sn IMC, which has quality concerning issue if the void’s density grows up. The first phase to form and grow into observable thickness for Ni and lead-free interface is Ni3Sn4 IMC, and the thickness has little relationship to the environmental stress, as no IMC thickness variation between TCT, uHAST and HTSL stress test. The more the Sn exists, the thicker Ni3Sn4 IMC will be derived from this experimental finding compare the Cu/Ni/SnAg cell and Ni/SnAg cell. Research limitations/implications The research found that FCCSP can pass automotive criteria that follow AEC-Q100, which give the confidence for upgrading the package type with higher efficiency and complexities of the pin design. Practical implications This result will impact to the future automotive package, how to choose the best package methodology and what is the way to do the package. The authors can understand the tolerance for the kind of flip chip package, and the bump structure is then applied for high-end technology. Originality/value The overall three kinds of bump structures, Cu/Ni/SnAg, Cu/SnAg and Ni/SnAg, were taken into consideration, and the IMC growing morphology had been recorded. Also, the IMC had changed during the environmental stress, and KV formation was reserved.

10 kV, 10 A Bipolar Junction Transistors and Darlington Transistors on 4H-SiC

2010 ◽  
Vol 645-648 ◽  
pp. 1025-1028 ◽  
Author(s):  
Qing Chun Jon Zhang ◽  
Robert Callanan ◽  
Anant K. Agarwal ◽  
Albert A. Burk ◽  
Michael J. O'Loughlin ◽  
...  
Keyword(s):  
Breakdown Voltage ◽  
Voltage Drop ◽  
Current Gain ◽  
Bipolar Junction Transistors ◽  
Collector Current ◽  
Forward Voltage ◽  
Collector Voltage ◽  
Forward Voltage Drop ◽  
Chip Size ◽  
Dc Current

4H-SiC Bipolar Junction Transistors (BJTs) and hybrid Darlington Transistors with 10 kV/10 A capability have been demonstrated for the first time. The SiC BJT (chip size: 0.75 cm2 with an active area of 0.336 cm2) conducts a collector current of 10 A (~ 30 A/cm2) with a forward voltage drop of 4.0 V (forced current gain βforced: 20) corresponding to a specific on-resistance of ~ 130 mΩ•cm2 at 25°C. The DC current gain, β, at a collector voltage of 15 V is measured to be 28 at a base current of 1 A. Both open emitter breakdown voltage (BVCBO) and open base breakdown voltage (BVCEO) of ~10 kV have been achieved. The 10 kV SiC Darlington transistor pair consists of a 10 A SiC BJT as the output device and a 1 A SiC BJT as the driver. The forward voltage drop of 4.5 V is measured at 10 A of collector current. The DC forced current gain at the collector voltage of 5.0 V was measured to be 440 at room temperature.

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