Pulsed power evaluation and simulation of high voltage 4H-SiC P-Type SGTOs

Abstract

Future Army pulsed power applications semiconductor devices that will meet requirements for highpower, low weight and volume, and fast switching speed. The following paper presents the pulsed power evaluation of high voltage silicon carbide (SiC) super gate turn-off (SGTO) thyristors. These devices are well suited for high voltage, high temperature pulsed power and continuous power electronic systems. A pulse-forming network (PFN) circuit and a low inductance, series resistor-capacitor (LRC) circuit were developed to evaluate both the fast dI/dt capability and the pulse safe operating area (SOA) of the SiC SGTO. Transient simulations of the high voltage SiC SGTOs were also performed on a narrow pulse LRC circuit to investigate the device's switching behavior under extreme pulsed conditions.

Physical insight into turn‐on transient of silicon carbide gate turn‐off thyristor

“…Actually, the evidence on the turn-on propagation phenomenon of SiC GTO is also indirect in other experimental researches. It was believed that the electric field is unevenly distributed along the Gate Runner of SiC GTO and the cells (regions) closer to the Gate Pad were turned on firstly, and subsequently the on-state areas expanded gradually [14,15,32]. The damaged regions within the failured device after pulsed current experimental tests were observed to be near the Gate Pad.…”

“…However, several problems hinder the development of SiC GTO specifically for the pulse power applications. Firstly, the tested pulsed current waveforms of high‐voltage SiC GTO thyristors from both our homemade one and those fabricated by Cree Inc. have confirmed that there is one extremely slow current rise process during the initial current pulse stage, which greatly degrades the turn‐on performance and generates a large gap from the expected di/dt , but this phenomenon has been inadvertently ignored by researchers till now (see Figure 1) [4, 14, 15]. Secondly, the current crowding phenomenon during the turn‐on transient has greatly threatened the high‐stress robustness and long‐term reliability of SiC GTO under repetitive pulsed current conditions [16, 17].…”

“…the development of device simulation model, exploration of practical applications, and reliability characterization [11][12][13][14][15][16][17][18][19].…”

“…The efforts made in these studies are undoubtedly valuable for further advancement of SiC GTO's device technology; however, the same attention has not been put onto the turn-on performance degradation issues of SiC GTO during the turnon transient process. Since it was verified by tested data that SiC GTO could provide around 60 times higher pulsed current density than traditional silicon power semiconductor devices, more and more efforts have also been concentrated on the evaluation of the fast switching on applications in recent years [8,[14][15][16][17][18]. It is commonly known that a high di/dt is usually required in the pulsed power applications, and mostly relays on the dynamic turn-on performance of the main power switch, SiC GTO.…”

“…Up to date, SiC GTO with a blocking voltage of 9 to 22 kV have been successfully developed, and there are continuous efforts made with the main focus on improving electrical performance of GTO and enhancing its reliability [8–10]. Besides these progresses made in device design and fabrication, considerable research works have also been concentrated on the development of device simulation model, exploration of practical applications, and reliability characterization [11–19].…”