Research On 6500V SiC ETO Simulation And Characteristics

In the high power applications,the capability of dv/dt,di/dt and voltage of the traditional silicon-based semiconductor has reached its own limits.The silicon carbide(SiC)power devices based on wide bandgap semiconductor material have great advantages than the device based silicon in high-power applications.The SiC MOSFETs,SiC IGBTs,SiC GTOs have been reported with the device technology development.Among the SiC high-voltage power devices,the gate turn-off thyristors(GTO)not only has the advantages of the high blocking voltage,the best current handling capability,fast turn-off,low leakage current and operating high temperature,but also the forward drop of GTO is lower than the same voltage level of IGBT and the conduction resistance of GTO is lower than MOSFETs.In addition,due to the limitations of gate oxide reliability,SiC IGBT and MOSFET can't work at high temperature.The voltage level of SiC GTO can realize 20kV,which can reduce the number of series devices and power losses.However,the GTO has some drawbacks,such as the need of snubber circuit during the turn-on and turn-off process and the driver circuit is complex.In order to improve the SiC GTO technology,the SiC ETO has great advantages.It has achieved snubberless turn-off capability and large RBSOA.In this paper,firstly,we introduced the development of SiC materials in terms of substrate materials,epitaxial materials and carrier lifetime.Then the structure and working principle of Si GTO and ETO,SiC GTO and ETO are demonstrated systematically.The research on SiC GTO and SiC ETO are analyzed in several years.In order to study the characteristics of SiC ETO,the two-dimensional structure model of SiC GTO and the Spice models of MOSFET and diode were established in ISE-TCAD software.Then the Mixed-mode simulation model of 6500V SiC ETO was established.We simulated the turn-on process of SiC ETO and analyzed the influence of the dc bias voltage,the drive current,different carrier lifetime of drift region during turn-on process.Also we researched the turn-off process of 6500 SiC ETO with the voltage from 1000V to 3000V.At the same time,we analayzed the dv/dt,di/dt,turn-off loss and turn-off speed of the SiC ETO.The simulation results show that the SiC ETO can realize the unity gain turn-off.Finally,we designed the package prototype and fast drive circuit of SiC ETO by using GeneSiC's commercial 6500V,40A SiC GTO and selecting the correct gate and emitter switches.A high voltage experiment platform for measuring the static and dynamic characteristics of SiC ETO was established.The low leakage current and the low conduction voltage drop of SiC ETO was verified by experiments.The turn-off waveform of SiC ETO was measured and studied by the experiments.The turn-off loss is only9.4mJ when the turn-off voltage and current was 3000V,2.3A.We also analyzed the factors that influence the turn-off time and demonstrated that the SiC ETO achieve the unit gain turn-off and low loss characteristics.The RBSOA of SiC ETO was discussed theoretically,and the future research work of 6500V SiC ETO is prospected.The simulations and experiments show that SiC ETO is a high-voltage and high-frequency device with wide application area in the future.It is of great significance to study the third generation of power semiconductor industry in China.