When the applied reverse voltage does not exceed a certain range, the current passing through the diode is the reverse current formed by the drift motion of a few carriers. The diode is cut off because the reverse current is very small. This reverse current is also called reverse saturation current or leakage current. The reverse saturation current of the diode is greatly affected by temperature.
The reverse current of A silicon tube is much smaller than that of A germanium tube. The reverse saturation current of A low-power silicon tube is on the order of nA, while that of A germanium tube is on the order of mua. When the temperature increases, the semiconductor is excited by heat, the number of minority carriers increases, and the reverse saturation current also increases.
