Design consideration for a germanium P-N-P-N switching device with three contacts and a "Sandwich" structure

The current Ioffthrough a germanium p-n-p-n switch in the OFF state is described as a simple function of the control current Itin its third contact. The device is of a so-called "sandwich" structure, the third contact being the outer edge of the middle layer. The voltages considered are sufficiently small so that avalanche multiplication can be neglected. It is derived that: and are device parameters determined by the physical and geometrical structure. The conditions for switching into the ON state are given and the temperature dependence of the parameters is predicted. The experimental results are found to be in good agreement with the design theory.