DC Characterization of Tunnel Diodes Under Stable Non-Oscillatory Circuit Conditions

A common problem in designing with Esaki tunneling diodes in circuits is parasitic oscillations, which occur when these devices are biased in their negative differential resistance (NDR) region. Because of this, the measured current-voltage (I-V) characteristics in the NDR region are usually incorrect, with sudden changes in current with voltage and a plateaulike waveform in this region. Using a full nonlinear analysis of the shunt-resistor-stabilized tunnel diode circuit, we have established the criteria for the range of element values that give stable operation. On this basis, I-V measurement circuits can be designed to be free from both low-frequency bias oscillations and high-frequency oscillations. The design equations lead to a direct I-V measurement setup in which the stabilization resistor in series with a capacitor can be employed. Experimental results validate the approach, and this is confirmed by second-derivative analysis (d²I/dV²) of the measured I-V characteristics.