Silicon carbide thyristors for electric guns

Abstract

The feasibility of using silicon power thyristors for electric gun pulsers has been established. The advantages of solid state switches are highly significant for electric gun systems. Nevertheless, the size and weight of a solid state pulser built using silicon devices is non-optimal due to limited device performance. The improved material properties of silicon carbide offer the potential of reducing the size and weight of the pulser by increasing device power density and di/dt capabilities. Studies have estimated the improvement to be a significant 60% reduction in both volume and weight, mainly due to improvement in di/dt capability. This improvement is highly desirable to build a solid state pulser capable of meeting the size and weight constraints of a tactical system. In this paper, we present a quantitative theoretical assessment of high-power silicon carbide (SiC) thyristor capabilities for EML applications based on the experimental evaluation of high power density prototype SiC thyristors and the design and performance modeling of a 4 kV SiC thyristor. This information provides the technical background to assess device performance improvement and claims for reduced pulser size and weight. This study confirms that a current density of 6 kA/cm/sup 2/ is feasible, and that a di/dt improvement of 2.5 times is a reasonable expectation, and further indicates the potential to operate SiC thyristors at current densities above 10 kA/cm/sup 2/ and at much higher di/dts.