@article{song_huang_lee_peng_2017, title={Theoretical and Experimental Study of 22 kV SiC Emitter Turn-OFF (ETO) Thyristor}, volume={32}, ISSN={["1941-0107"]}, DOI={10.1109/tpel.2016.2616841}, abstractNote={Controllable three terminal high voltage (<inline-formula><tex-math notation="LaTeX">$>$</tex-math> </inline-formula>10 kV) power switches based on silicon carbide (SiC) material are gaining significant attentions since silicon (Si) power switches such as insulated gate bipolar transistors (IGBTs) are typically designed for much lower blocking voltages. After more than 30 years of commercial development, there is a fundamental limitation in designing Si IGBTs with more than 6.5 kV voltage rating. On the other hand, the voltage barrier for SiC power devices could easily exceed 10 kV. In this paper, a world record 22 kV SiC p-type emitter turn-<sc>OFF</sc> (ETO) (p-ETO) thyristor is reported and analyzed as a promising candidate for high-voltage applications, such as solid-state circuit breaker, HVdc, flexible alternating current transmission system (FACTS), and motor drives. The device is based on a 2 cm<sup>2 </sup> 22 kV p-type SiC gate turn-<sc>off</sc> thyristor (p-GTO) structure. Its static performances are analyzed exhibiting a high voltage (22 kV) blocking characteristic, ultralow leakage current, and a low forward voltage drop ( <inline-formula><tex-math notation="LaTeX">$\sim$</tex-math></inline-formula>7 V at 100 A) for a broad range of temperatures. The dynamic performances including turn-<sc>on</sc> and turn-<sc>off</sc> are studied. Key switching characteristics such as turn-<sc>off</sc> storage time, turn-<sc>off</sc> loss, <italic>dv/dt</italic>, and <italic> di/dt</italic> are presented and analyzed. In addition, the large reverse biased safe operation area (RBSOA) of the 22 kV SiC ETO is theoretically analyzed and verified by simulations and experimental tests.}, number={8}, journal={IEEE TRANSACTIONS ON POWER ELECTRONICS}, author={Song, Xiaoqing and Huang, Alex Q. and Lee, Meng-Chia and Peng, Chang}, year={2017}, month={Aug}, pages={6381–6393} }
 @inproceedings{song_huang_lee_peng_cheng_o'brien_ogunniyi_scozzie_palmour_2015, title={22 kV SiC emitter turn-off (ETO) thyristor and Its dynamic performance including SOA}, DOI={10.1109/ispsd.2015.7123443}, abstractNote={Ultra-high voltage (>10 kV) power devices based on SiC are gaining significant attentions since Si power devices are typically at lower voltage levels. In this paper, a world record 22kV Silicon Carbide (SiC) p-type ETO thyristor is developed and reported as a promising candidate for ultra-high voltage applications. The device is based on a 2cm2 22kV p type gate turn off thyristor (p-GTO) structure. Its static as well as dynamic performances are analyzed, including the anode to cathode blocking characteristics, forward conduction characteristics at different temperatures, turn-on and turn-off dynamic performances. The turn-off energy at 6kV, 7kV and 8kV respectively is also presented. In addition, theoretical boundary of the reverse biased safe operation area (RBSOA) of the 22kV SiC ETO is obtained by simulations and the experimental test also demonstrated a wide RBSOA.}, booktitle={Proceedings of the international symposium on power semiconductor}, author={Song, X. Q. and Huang, A. Q. and Lee, M. C. and Peng, C. and Cheng, L. and O'Brien, H. and Ogunniyi, A. and Scozzie, C. and Palmour, J.}, year={2015}, pages={277–280} }
 @inproceedings{lee_wang_huang_2015, title={4H-SiC 15kV n-IGBT physics-based sub-circuit model implemented in Simulink/Matlab}, DOI={10.1109/apec.2015.7104478}, abstractNote={A physics-based 15kV 4H-SiC n-IGBT sub-circuit model implemented in Simulink/Matlab is demonstrated in this work. Two-phase voltage ramp during the switching before and after punch through is well predicted. Simulated with a simple 4H-SiC Schottky diode model, the switching results is experimentally verified. The current bump during turn-off and current overshoot during turn-on are well-predicted and can be explained by the instantaneous output capacitances of the IGBT and Schottky diode. The computing speed for the full turn-on and off with stray inductance is approximately 2 minutes.}, booktitle={2015 thirtieth annual ieee applied power electronics conference and exposition (apec 2015)}, author={Lee, M. C. and Wang, G. Y. and Huang, A. Q.}, year={2015}, pages={1051–1057} }
 @inproceedings{lee_song_huang_2015, title={Excess carrier mapping technique -A new parameter extraction method for 4H-SiC ambipolar power devices}, booktitle={WiPDA 2015 3rd IEEE Workshop on Wide Bandgap Power Devices and Applications}, author={Lee, M. C. and Song, X. Q. and Huang, A.}, year={2015}, pages={51–55} }
 @inproceedings{song_huang_lee_peng_2015, title={High voltage Si/SiC hybrid switch: An ideal next step for SiC}, DOI={10.1109/ispsd.2015.7123446}, abstractNote={Silicon carbide (SiC) power switches such as MOSFET or JFET have demonstrated their superior advantages over silicon (Si) power devices such as IGBT, especially in terms of significantly reduced switching losses. A major issue facing large scale adoption of SiC power devices is still the much higher cost. This paper proposes that Si/SiC hybrid switch should be a natural next step moving forward for high voltage applications to address the cost issue. In the proposed Si/SiC hybrid switch, a SiC MOSFET is connected in parallel with Si IGBT to combine the advantages of IGBT and MOSFET. This concept can also works well with SiC JFET. A 6.5 kV Si IGBT and SiC MOSFET hybrid switch is developed as an example to demonstrate its superior cost/performance. The switching loss can be reduced by more than 70% at a cost of only 50% higher compared to Si IGBT. This work is especially essential for high voltage applications such as medium voltage motor drive, FACTS and HVDC systems.}, booktitle={Proceedings of the international symposium on power semiconductor}, author={Song, X. Q. and Huang, A. Q. and Lee, M. C. and Peng, C.}, year={2015}, pages={289–292} }
 @inproceedings{liang_huang_sung_lee_song_peng_cheng_palmour_scozzie_2015, title={Turn-on capability of 22 kV SiC Fmitter Turn-off (ETO) Thyristor}, DOI={10.1109/wipda.2015.7369275}, abstractNote={The turn-on characteristics for the SiC p-ETO are researched in this paper. By establishing the two-dimensional numerical model of the SiC p-ETO, the influence of the device parameters and external circuit conditions on the turn-on speed is discussed. The experiments agree with the simulated results well. The npn turn-on mode of ETO is captured in a high di/dt experiment, which proves the existence of the FBSOA for this time hence the possibility of its application in converters without di/dt snubber. According to the intrinsic temperature limitation of the SiC material, the simulation shows that the peak power density of the SiC p-ETO during turn-on could reach several tens of MW/cm2.}, booktitle={WiPDA 2015 3rd IEEE Workshop on Wide Bandgap Power Devices and Applications}, author={Liang, L. and Huang, A. Q. and Sung, W. J. and Lee, M. C. and Song, X. Q. and Peng, C. and Cheng, L. and Palmour, J. and Scozzie, C.}, year={2015}, pages={192–195} }
 @article{lee_huang_2014, title={An injection efficiency model to characterize the injection capability and turn-off speed for > 10 kV 4H-SiC IGBTs}, volume={93}, ISSN={["1879-2405"]}, DOI={10.1016/j.sse.2013.12.008}, abstractNote={This work analytically formulates the relationship among the followings for characterization purpose: (i) γE (injection efficiency), (ii) excess charge stored during on-state and (iii) charge extraction rate and voltage ramp before punch-through during the turn-off. Injection efficiency is expressed in terms of JR (reference current density), Jb (buffer layer reference current), and JT (terminal current). Both JR and Jb are lumped parameters and can be extracted without any knowledge of parameters in the emitter and buffer layer. While γE is simply the ratio of minority to total current, injection capacity is defined mathematically in this work as an index of the tendency of the excess carriers being injected from emitter and then stored in the drift region. 4H-SiC p- and n-IGBT will be discussed side-by-side throughout the discussion. The adaptability of this injection efficiency model will be examined under different emitter conditions and buffer layer lifetimes. This work is also applicable to silicon devices.}, journal={SOLID-STATE ELECTRONICS}, author={Lee, Meng-Chia and Huang, Alex Q.}, year={2014}, month={Mar}, pages={27–39} }
 @inproceedings{lee_huang_huang_brunt_2013, title={An analytical investigation of the effect of varied buffer layer designs on the turn-off speed for 4H-SiC IGBTs}, DOI={10.1109/wipda.2013.6695559}, abstractNote={We propose a criterion to quantify the relationship between buffer layer parameters at a given total charge and turn-off speed for 4H-SiC IGBTs. Three phases of voltage ramp are analytically discussed during the inductive load turn-off by solving each corresponding continuity equation. Extra emphasis will be placed on Phase II - a transition phase in between the initial voltage ramp and punch-through.}, booktitle={2013 1st IEEE Workshop on Wide Bandgap Power Devices and Applications (WiPDA)}, author={Lee, M. C. and Huang, X. and Huang, A. and Brunt, E.}, year={2013}, pages={44–47} }
 @inproceedings{lee_huang_huang_2012, title={An accurate prediction of two-dimensional carrier density profile in IGBT and its significances on steady-state and transient analysis}, DOI={10.1109/ecce.2012.6342637}, abstractNote={This work presents a piecewise two-dimensional steady-state analytical model for insulated gate bipolar transistor (IGBT). The proposed model can accurately describes the dependence of carrier density profile on the ratio of accumulation gate width (Lg) to the half cell width (Lcell) without ignoring the recombination in the drift region. The drift region of IGBT is divided into four regions in this model. By determining the boundary that separates one- and two-dimensional regions, the carrier density profiles in the four regions can be derived with proper boundary conditions. The model is originally developed for, but not limited to, 4H-SiC p-IGBT. The results of proposed model are in good agreement with the simulation results at varied current densities and with different values of Lg/Lcell. The I-V curves in the linear region generated by the proposed model match well with the simulated results. The error of the amount of stored charge generated by one-dimensional model will also be examined.}, booktitle={2012 IEEE Energy Conversion Congress and Exposition (ECCE)}, author={Lee, M. C. and Huang, X. and Huang, A. Q.}, year={2012}, pages={1496–1502} }
 @inproceedings{huang_wang_lee_huang_2012, title={Reliability of 4H-SiC SBD/JBS diodes under repetitive surge current stress}, DOI={10.1109/ecce.2012.6342436}, abstractNote={The reliability of power diode under surge current stress is crucial to the applications like motor drives. In this paper, the single and repetitive surge reliability of the 4H-SiC Schottky Barrier Diodes (SBDs) and Junction Barrier Schottky (JBS) diodes have been tested and the corresponding failure mechanisms studied. The single surge test results of two SBDs and three JBS didoes suggest a 450W/mm2 constant power line of the safe operation area for single surge current with a half sinusoidal pulse width of 8.3ms. The stress tests show no degradation of SBDs up to 10,000 cycles of surge current below 34.9A/mm2. The JBS diodes show VF degradation after surge stress at different current levels, which might be dependent on the hole injection levels. The aluminum metallization and bipolar degradation are the main limits for the reliability of SiC diodes under surge conditions.}, booktitle={2012 IEEE Energy Conversion Congress and Exposition (ECCE)}, author={Huang, X. and Wang, G. Y. and Lee, M. C. and Huang, A. Q.}, year={2012}, pages={2245–2248} }