The design and performance of a high-speed silicon diode

With the increasing use of high-speed switching techniques a need has arisen for diodes with a fast transient response. The paper first considers the various methods by which the speed of semiconductor diodes may be improved by reducing carrier storage. In the silicon device described, this is accomplished by a reduction of the lifetime of the basic material. Of the two methods investigated, neutron bombardment and heat treatment, the latter was found to be the more effective. The heat treatment involves quenching the silicon from a temperature in excess of 1000°C. The paper then discusses the effect on the static characteristics of diodes made from silicon quenched in this manner. As a consequence of the reduction in lifetime the conductivity modulation of the base region is decreased, resulting in an inferior forward characteristic. In general, the reverse currents and breakdown voltages found are somewhat higher than in devices made with untreated material. A typical diode fabricated from silicon quenched from 1150°C passes a forward current of 10 mA at 1 volt, and has a reverse current of 0.1 ¿A at ¿100 volts. The methods of measuring the transient response of the device are discussed, and a comparison is made between them. A typical device has a switching time less than 0.2 microsec and a total recovered charge of 10¿10 coulomb.