The design and construction of tunnel diodes

The electrical characteristics and principle of operation of two types of tunnel device are described: the tunnel diode and the uni-tunnel or backward diode. The considerations governing choice of base and alloying materials are discussed. Details are given of the processes used to manufacture germanium and gallium arsenide devices, particular attention being given to the method of achieving close tolerance of the peak current of tunnel diodes by a monitored etching technique. Results are presented which show the influence of processing parameters on device characteristics. The equivalent circuits of the devices are related to the basic properties of the elements and their encapsulation.