The Army Research Laboratory collaborated with Silicon Power Corporation to package sixteen parallel 9 kV, 1.0 cm 2 silicon carbide (SiC) super gate turn-off thyristors (SGTOs) in a single 82 cm 3 module using Silicon Power's materials and techniques from silicon packaging. The peak current switched was 84 kA for a 43-μs pulse width as measured at half-maximum. The rising slope calculated from 10-90% of the peak was 10 kA/μs, and the action under the curve was 2.6 × 10 5 A 2 s. Results encouraged further development of larger-area devices with higher 15 kV blocking in order to fully utilize the package area and create a single-layer >10 kV pulse switch. Challenges in the development of this SiC SGTO module include optimizing SiC material uniformity and device yield, controlling turn-on of sixteen parallel devices, and maximizing high-voltage blocking of the complete package.

Newly designed, high-power silicon gate turn-off thyristors are being evaluated to satisfy the U. S. Army's need for compact, lightweight pulse switches. Following the successful demonstration of a 3.5 cm 2 silicon Super-GTO, Silicon Power Corporation re-designed the emitter layout and increased the device footprint to create a switch optimized for use in high-current, wide-pulse applications. The 7 cm 2 silicon “Stitch” Super-GTO was developed to block 7 kV. The 2x increase in die size actually results in a 2.5x increase in active area because a portion of chip area that was previously taken up by perimeter high voltage termination is now used for conduction. The Super-GTOs were evaluated at the Army Research Laboratory in a low-inductance pulse-forming network. Pulse current was successfully stepped up as high as 35 kA, corresponding to a current density of 5 kA/cm 2 over the chip's footprint. This corresponds to 7 kA/cm 2 over the active emitter area, when the edge termination is excluded. Compared to Silicon Power's original device, the new larger component conducted 40% higher current density. The 35 kA current pulse had a width of 125 μs and an I 2 t of 9.2 ×10 4 A 2 s. The 10-90% rise of the current pulse was 2.4 kA/μs, and the maximum on-state forward conduction drop was 28 V. Given good processing and packaging yields, this larger Stitch Super-GTO can greatly reduce the size of high current pulse switches.

Power devices made on Silicon Carbide (SiC) are expected to offer significant advantages over silicon due to the unique material properties. With the continuing improvement in both material quality (defect density and carrier lifetime) and SiC device fabrication process, SiC power devices are increasingly fabricated with higher blocking rating and larger die size. This paper describes the benefits of using SiC Gate Turn-Off thyristors (GTO) in power electronics, especially for pulse power applications, reviews the development history and the current state of the art, and outlines the future perspective for developing large area GTOs with high blocking voltage of > 10 kV.Experimental results for the state-of-the-art 9 kV, 1 cm(2) SiC GTOs are presented. Static and dynamic characteristics are described. A forward drop of 3.7 V at 100 A (100 A/cm(2)) is measured at 25 degrees C. A slight positive temperature coefficient of the forward drop is present at 300 A/cm(2) indicating the possibility of paralleling multiple devices for higher current capability. The device exhibits extremely low leakage currents at high temperatures. The turn-on delay is found to be a strong function of the gate current, cathode-anode current and voltage. A peak current of 12.8 kA conducted with a pulse width of 17.4 mu s indicating the superiority of the SiC GTOs for pulse power applications.

The U.S. Army Research Laboratory (ARL) has been investigating silicon super gate turn-off thyristors (SGTOs) for high action pulse switching necessary for Army survivability and lethality applications. The silicon SGTO designed by Silicon Power Corporation (SPCO) was evaluated to determine its repeatable pulse current capability at a 1 ms pulse width. The initial SGTO design was a 3.5 cm2 chip rated for 4 kV forward blocking and 10 kA peak current at 10 µs pulse width or 100 A continuous. The previous work by ARL on these switches reported repetitive peak current of 5 kA with a charge voltage of 4 kV. Additionally, the switches failed short at peak currents of 6 kA, with calculated action of 1.3 × 104 A2 s at 5 kA. This work highlights the device optimization that SPCO has since made on the Si SGTO to improve the device pulsing performance. The latest Si SGTO evaluated maintains the same chip area and active area as the previous devices. Modification to the mask layout and the enhancement of the emitter design enables the latest Si SGTO to exhibit repeatable peak current of 5.5 kA (a 10% increase compared to the previous batch). The calculated action for the latest switches was 1.6 × 104 A2s at 5.5 kA.

Power devices made on Silicon Carbide (SiC) are expected to offer significant advantages over silicon due to the unique material properties. With the continuing improvement in both material quality (defect density and carrier lifetime) and SiC device fabrication process, SiC power devices are increasingly fabricated with higher blocking rating and larger die size. This paper describes the benefits of using SiC Gate Turn-Off thyristors (GTO) in power electronics, especially for pulse power applications, reviews the development history and the current state of the art, and outlines the future perspective for developing large area GTOs with high blocking voltage of > 10 kV. Experimental results for the state-of-the-art 9 kV, 1

The U.S. Army Research Laboratory (ARL) has been investigating silicon super gate turn-off thyristors (SGTOs) for high action pulse switching necessary for Army survivability and lethality applications. The silicon SGTO designed by Silicon Power Corporation (SPCO) was evaluated to determine its repeatable pulse current capability at a 1 ms pulse width. The initial SGTO design was a 3.5 cm 2 chip rated for 4 kV forward blocking and 10 kA peak current at 10 ¿s pulse width or 100 A continuous. The previous work by ARL on these switches reported repetitive peak current of 5 kA with a charge voltage of 4 kV. Additionally, the switches failed short at peak currents of 6 kA, with calculated action of 1.3 × 10 4 A 2 s at 5 kA. This work highlights the device optimization that SPCO has since made on the Si SGTO to improve the device pulsing performance. The latest Si SGTO evaluated maintains the same chip area and active area as the previous devices. Modification to the mask layout and the enhancement of the emitter design enables the latest Si SGTO to exhibit repeatable peak current of 5.5 kA (a 10% increase compared to the previous batch). The calculated action for the latest switches was 1.6 × 10 4 A 2 s at 5.5 kA.