| 1. |
- Domeij, Martin, et al.
(author)
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2.2 kV SiC BJTs with low V(CESAT) fast switching and short-circuit capability
- 2010
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In: SILICON CARBIDE AND RELATED MATERIALS 2009, PTS 1 AND 2. ; , s. 1033-1036
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Conference paper (peer-reviewed)abstract
- This paper reports large active area (15 mm(2)) 4H-SiC BJTS with a low V(CESAT)=0.6 V at 1(C)=20 A (J(C)=133 A/cm(2)) and an open-base breakdown voltage BV(CEO)=2.3 kV at T=25 degrees C. The corresponding room temperature specific on-resistance R(SP.ON)=4.5 m Omega cm(2) is to the authors knowledge the lowest reported value for a large area SiC BJT blocking more than 2 kV. The onstate and blocking characteristics were analyzed by device simulation and found to be in good agreement with measurements. Fast switching with VcE rise- and fall-times in the range of 20-30 ns was demonstrated for a 6 A 1200 V rated SiC BJT. It was concluded that high dynamic base currents are essential for fast switching to charge the BJT parasitic base-collector capacitance. In addition, 10 mu s short-circuit capability with V(CE)=800 V was shown for the 1200 V BJT.
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| 2. |
- Gumaelius, Lena, 1967-, et al.
(author)
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The role of entrepreneurial skills in engineering education : A case study performed in Denmark, Japan, Korea and Sweden
- 2017
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In: Proceedings of the 45th SEFI Annual Conference 2017 - Education Excellence for Sustainability, SEFI 2017. - : European Society for Engineering Education (SEFI). - 9789899887572 ; , s. 593-602
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Conference paper (peer-reviewed)abstract
- The importance of teaching entrepreneurial skills has been on the agenda for several years. But how do engineering education institutes (EEIs) serve as institutions facilitating the learning of these skills? In this study, we compare four EEIs from four countries located in two global regions, East Asia and the Northern Europe, in order to identify models for how education in entrepreneurship can be implemented according to each country's situation. We use a modified version of Dahlöf and Lundgren's frame-factor theory to analyse how the universities understand the internal and external driving forces for the development of this kind of education. We also address how these frame factors affect the development processes at each EEI. The study identifies differences in these processes, which depend on how pressures originating outside the universities are expressed.
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| 3. |
- Konstantinov, A., et al.
(author)
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Operation of Silicon Carbide BJTs Free from Bipolar Degradation
- 2010
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In: SILICON CARBIDE AND RELATED MATERIALS 2009, PTS 1 AND 2. ; , s. 1057-1060
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Conference paper (peer-reviewed)abstract
- The mechanisms of bipolar degradation in silicon carbide BJTs are investigated and identified. Bipolar degradation occurs as result of stacking fault (SF) growth within the low-doped collector region. A stacking fault blocks vertical current transport through the collector, driving the defective region into saturation. This results in considerable drop of emitter current gain if the BJT is run at a reasonably low collector-emitter bias. The base region does not play any significant role in bipolar degradation. Long-term stress tests have shown full stability of large-area high-power BJTs under minority carrier injection conditions provided the devices are fabricated using low Basal Plane Dislocation (BPD) material. However, an approximately 20% current gain compression is observed for the first 30-60 hours of burn-in under common emitter operation, which is related to instability of surface recombination in the passive base region.
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