Abstract :
This paper describes design, development, characterization, and operation of a two-terminal, high-current, high-voltage silicon four-layer diode. The main feature of this new four-layer diode is a voltage-current characteristic which is, prior to switching, similar to that of an avalanche diode. This property is achieved by short-circuiting one emitter-base junction, resulting in a grid-type emitter geometry. The short-circuiting takes place over the entire device area in order to maintain uniform turn-on and uniform current conduction. Devices switching at 1000 volts or higher, with peak pulse current capability of 1000 amperes or more, are described. To achieve very high switching voltages, the stacking of two or three silicon chips was found to be useful. Extended tests Were performed at various combinations of pulsewidths (0.5 to 12 µs), repetition rates (0.2 to 2000 pulses per second), and operating times (0.1 to 2500 hours). The test circuits and the resulting turn-on and recovery times are summarized, Failure analysis establishes hot spot development or thermal fatigue as possible failure mechanisms. Since series operation of many devices is possible without complicated dividing networks, the complexity of pulse modulator circuitry is reduced, and resonantly charged circuits can exhibit a high degree of operation reliability and temperature insensitivity.
