High-Frequency Negative-Resistance Circuit Principles for Esaki Diode Applications

The Esaki 1 diode ( or tunnel diode) exhibits a negative-resistance characteristic in the forward-biased region as shown in Fig. 1. This is a "voltage-controlled" type of characteristic in that the current is a singlevalued function of voltage. Fig. 1 is a static curve, but the negative resistance is believed to remain effective at extremely high frequencies. Oscillation in the microwave range has been observed by several workers.2,3,4 It is suspected that useful negative-resistance effects will also become obtainable in the millimeter wave range as our technology improves. There is also a capacitance across the junction. This is quite high by comparison with other junction diodes, when measured per unit area 477 478 T H E B E L L SYSTEM T E C H N I C A L J O U R N A L , MAY 1 9 6 0 or DC D U 0 0.1 0.2 VOLTAGE 0.3 0.4 0.5 Fig. 1 -- The current-voltage characteristic of an Esaki diode. The general curve shape is variable to a small degree, and the current density to a large degree, depending upon the semiconductor materials and processing. The total current is also proportional to diode junction area.