High speed Esaki switching diodes

Esaki diode-transistor circuits have demonstrated potential switching speeds of less than one milli-microsecond. Such circuits require Esaki diodes with extremely low junction capacitances, and peak currents generally between one and six milliamperes. This paper describes the design and construction of very high speed, low peak current, germanium Esaki switching diodes. A design criteria is presented which demonstrates the various interactions and limitations between (capacitance/peak current), peak current, and series resistance. Limitations imposed by junction geometry are also presented. The design of a particular high speed Esaki diode with a peak current of five milliamperes, and a junction capacitance of three picofarads, is given together with experimental results. Methods for producing germanium Esaki diodes with peak current tolerances of ± 1% and peak-to-valley ratios as high as 25 : 1 are described.