Electrical breakdown in germanium p-n junction

When square-wave pulses of 5¿160 microsec duration with a repetition rate of 1000 pulses/sec are applied in the reverse direction across a germanium grown p-n junction, the critical voltage of avalanche inception rises with the temperature of the specimen. The temperature coefficient is estimated to be about 8 × 10-4 per deg C, and the maximum field intensity in the junction is about 265 kV/cm. On the other hand, the turn-over voltage decreases markedly with the increasing ambient temperature of the specimens and duration of the pulses. The barrier temperature at turn-over is considered by the two methods for grown-junction and point-contact diodes. One is based on the temperature dependence of the reverse saturation current, which is measured at the interval of applied pulse, and the other is on the turn-over power at different ambient temperatures. From these experimental results it is concluded that there may be non-uniformity of junction or patch in the high electric field, and turn-over occurs when the barrier temperature reaches the intrinsic temperature at any spot in the junction.