F. Udrea's research while affiliated with Cambridge Consultants Ltd and other places

... However, high dV/dt also causes EMI noise that can interfere with nearby circuitry, such as microcontrollers, memories, or measurement equipment, indirectly impacting the reliability of SiC IGBTs. It also makes power converter design more complex in various ways as was explained in [32]. Therefore, controlling the dV/dt on the device level will reduce the time and effort required for converter development, improve its ruggedness, and optimize costs. ...

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Silicon Carbide n-IGBTs: Structure Optimization for Ruggedness Enhancement

... These techniques include self-aligned channel [2,3], self-aligned source contact [4], specific doping on JFET region [5], and current spreading layer [6]. On the design front, cell topology and pitch reduction play vital roles in further improving the performance of VDMOSFETs [7][8][9][10][11][12][13][14][15][16]. ...

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Design and Characterization of Cell Topology Effect on SiC VDMOSFETs for High Power and Frequency Applications

... To achieve a lower R on,sp and V on , a thinner drift layer and the use of lower work-function metal (like TiN, Mo, Ti) can be employed. In addition, a super-junction, a novel structural concept with a challenging fabrication process, can be considered, which further relaxes the stress relationship between V on and reverse leakage current, as extensively reported in SiC, [24][25][26] and sparingly reported in GaN, 27) β-Ga 2 O 3 . 28) ...

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High breakdown voltage of 1.3 kV and low turn-on voltage of 0.48 V β-Ga2O3 heterojunction barrier Schottky diode with tungsten Schottky contact

... The heat transfer from a heated structure to the surrounding gas will be higher for gases with a higher thermal conductivity. Thermal conductivity-based gas sensors have advantages, including eliminating catalysts and adsorbents [5,6]. Moreover, thermal conductivity gas sensors have been found in many applications, including coal mines, natural gas monitoring (for methane sensing), and light gases such as hydrogen [7]. ...

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Modeling and Design Parameter Optimization to Improve the Sensitivity of a Bimorph Polysilicon-Based MEMS Sensor for Helium Detection

... This may lead to the inapplicability of the gate lifetime obtained from DC tests to device operations in power converters. Recently, a circuit method is proposed to evaluate the gate lifetime under the inductive load switching [225], the condition of which is not accessible by DC or pulse I-V methods. As the parasiticinduced gate overshoot has a resonance nature, this method features a resonance-like gate ringing with the pulse width down to 20 ns and an inductive switching concurrently in the drain-source loop. ...

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Stability, Reliability, and Robustness of GaN Power Devices: A Review

... During the fast voltage rising phase, the voltage can increase as fast as several hundred kV/μs, which can cause long-term reliability issues. Our previous work [29], explained in detail that positive and negative voltage spikes are induced into the gate electrode due to this high dV/dt which can either cause unintentional turn-on of the IGBT or stress the gate oxide. This issue is particularly severe in bridge-leg configurations ( Fig. 6(a)), such as DC/DC converters or inverters, where positive and negative gate voltage spikes can be produced in the low-side switch during the switching transient of the high-side switch and vice versa ( Fig. 6(b)) leading to short-circuiting of the DC bus. ...

Reference:

Silicon Carbide n-IGBTs: Structure Optimization for Ruggedness Enhancement

... In the plateau region, while the drain voltage (V DS ) slowly decreases, the freewheeling Schottky diode begins to form a depletion region to support 400 V. As a result, the displacement currents from the Schottky diode are added to the drain current, leading to an instantaneous increase in the MOSFET's drain current, as shown in Fig. 8 [22]. ...

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Gamma Ray on Superjunction MOSFET and Gate Ringing

... Furthermore, 10 400-V BV was obtained on HEMTs with an L GD of 125 µm by means of a thick poly-AlN passivation layer [21]. Furthermore, pioneering multidimensional device architectures were proposed to balance V BD and R ON [22]. ...

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Demonstration of $>$8-kV GaN HEMTs With CMOS-Compatible Manufacturing on 6-in Sapphire Substrates for Medium-Voltage Applications

... An initial attempt to present the short circuit behaviour of a the conventional structure of a 10 kV-rated IGBT was done in [38] and showed that the device can fail due to parasitic thyristor latching, caused by a positive feedback mechanism that increases temperature and current density, and high leakage current flowing inside the IGBT during the blocking state after the short-circuit has been detected and the device turned off. The latter mechanism can cause the IGBT to fail several > REPLACE THIS LINE WITH YOUR MANUSCRIPT ID NUMBER (DOUBLE-CLICK HERE TO EDIT) < hundred microseconds after it has been turned off, a behaviour that is similar to what has been observed in silicon IGBTs [39] and SiC MOSFETS [40]. Figure 13 shows that the same failure mechanisms exist in the 27 kV validated IGBT during a short circuit event under hard switching at a DC voltage of 14 kV, gate to emitter voltage of 15 V and stray inductance of 100 nH. ...

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Silicon Carbide n-IGBTs: Structure Optimization for Ruggedness Enhancement

... The parallel connection of a sense transistor (sense-FET, also called sense-HEMT or sense-GaN for GaN HEMTs [30]) does not require the critical loop to be cut, and can be also monolithically integrated with the GaN IC. GaN-based sense-FET ICs have been already demonstrated monolithically [31][32][33][34][35][36][37] and also by external wiring of several GaN devices [30,38] for single discrete transistors and used in half-bridges. This work focuses only on current-mirror sensing; other current sensing methods such as shunt-sensor [39][40][41][42][43] or hall-sensor [44] integration, as well as related magnetic flux concentrators [45] or magnetic sensors [46], were also demonstrated in GaN technologies. ...

Reference:

Three-Phase Motor Inverter and Current Sensing GaN Power IC