| 1. |
- Domeij, Martin, et al.
(författare)
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2.2 kV SiC BJTs with low V(CESAT) fast switching and short-circuit capability
- 2010
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Ingår i: SILICON CARBIDE AND RELATED MATERIALS 2009, PTS 1 AND 2. ; , s. 1033-1036
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Konferensbidrag (refereegranskat)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. |
- Konstantinov, A., et al.
(författare)
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Operation of Silicon Carbide BJTs Free from Bipolar Degradation
- 2010
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Ingår i: SILICON CARBIDE AND RELATED MATERIALS 2009, PTS 1 AND 2. ; , s. 1057-1060
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Konferensbidrag (refereegranskat)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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| 3. |
- Nawaz, M, et al.
(författare)
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A theoretical optimization of GaInP/GaInAs/GaAs based 980 nm Al-free pump laser using self-consistent numerical simulation
- 2003
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Ingår i: Solid-State Electronics. - : Elsevier Science B.V., Amsterdam.. - 0038-1101 .- 1879-2405. ; 47:2, s. 291-295
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Tidskriftsartikel (refereegranskat)abstract
- Using self-consistent two-dimensional numerical simulation (LASTIP), the layer structure of the laser diodes is optimized. A ridge waveguide structure with GaInAs/GaAs and GaInAs/GaInAsP active regions has been simulated. The influence of the well numbers and waveguide thicknesses on the threshold current is studied. Compared to GaInAs/ GaAs, GaInAs/GaInAsP active region suffers from larger spread in the threshold current due to non-uniformities in the carrier density with increasing quantum wells. Simulations have been performed for different temperatures and at different cavity lengths.
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| 4. |
- Nawaz, M., et al.
(författare)
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Assessment of High and Low Temperature Performance of SiC BJTs
- 2009
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Ingår i: SILICON CARBIDE AND RELATED MATERIALS 2008. - STAFA-ZURICH : TRANS TECH PUBLICATIONS LTD. ; , s. 825-828
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Konferensbidrag (refereegranskat)abstract
- This paper addresses the performance of SiC NPN Bipolar Junction Transistors (BJTs) at high and low temperature. A current gain of 50 at room temperature was obtained which decreases to 25 at 275 degrees C. A maximum current gain (beta) of 111 has been reported at -86 degrees C. At low temperature (below -86 degrees C), the current gain drops rapidly because of carrier freezout effect. At room temperature, a minimum on-resistance of 7 m Omega-cm(2) was obtained. This increases to 28 m Omega-cm(2) at 275 degrees C. The on-resistance of BJTs is approximately unaffected by lowering the temperature down to -86 degrees C front room temperature. Below -86 degrees C, the on-reststance JUMPS up rapidly because of carrier freezeout. Electrical performance of BJTs have been fairly stable during stress measurement at high temperature (120 hours at 100 degrees C) at a collector bias of 1000V (with open base) for devices with a breakdown voltage of 1200VA. The devices have been stressed further at low (i.e., 6) and high gain (i.e., 15) at room temperature. Initial degradation within first hour of stress test has been reported and then degradation stabilizes out. Packaged devices were tested Lip to 550 degrees C and performed admirably well up to that temperature.
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| 5. |
- Nawaz, M., et al.
(författare)
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Radiation hardness assessment of high voltage 4H-SiC BJTs
- 2009
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Ingår i: Device Research Conference, 2009. DRC 2009. - 9781424435289 ; , s. 279-280
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Konferensbidrag (refereegranskat)abstract
- Silicon carbide (SiC) based bipolar junction transistors (BJTs) are in teresting can didates fo r high temperature and for high power applications primarily due to their low conduction losses and fast switching capability. While excellent room temperature characteristics in terms of high breakdown voltage, low on-resistance and high gain [1, 2] have bee n reported, very limited datais available for their assessment in extreme harsh environment (e.g., high temperature and/or radiation) where the conventional Si devices T4, 5] do not offer acceptable functionality. SiC based BJTs [3] have been irradiated with protons and 13C ions and show fairly stable electrical behavior with proton fluence up to 5 × 1010 p/cm-2 and 13C ions fluence up to 5 × 10 10 cm-2. Early results on neutron irradiated 6H-S1C JFETs [6] showed no significant change at fluences up to 1 × 1015 n/cm2, but degradation was increased significantly with additional fluence due to the introduction of dee p-level traps. Similarly, recent studies on SiC JF ETs and Schottly diodes with gamma rays (60Co) and protons reported no degradation from gamma rays up to a dose of ∼ 6 Mrad but high energy protons (63 MeV) at the fluence of 5 × 1015 p/cm 2 induced an 80 % reduction in saturated drain current [7] This work demonstrates for the first time the suitability of SiC-B JTs when irradiated with gamma rays.
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| 6. |
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| 7. |
- Persson, L., et al.
(författare)
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Separation of mass-overlapped time of flight-energy elastic recoil detection analysis data using Ryan and Jamieson's dynamic analysis method
- 2001
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - 0168-583X .- 1872-9584. ; 179:3, s. 403-411
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Tidskriftsartikel (refereegranskat)abstract
- Time of flight-energy (ToF-E) elastic recoil detection analysis (ERDA) data often contains mass signals with considerable overlap from adjacent isotopes in the mass-energy plane. An evaluation has been carried out of the suitability of the dynamic analysis method proposed by Ryan and Jamieson to decompose elemental signals with overlapping mass. This method is shown to work very well on generated test data and the result when it was applied to experimental data appears quite promising. Very accurate mass calibration and lineshape determination was found to be a prerequisite for the application of the method.
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