Correlation of reverse leakage current conduction mechanism and electrostatic discharge robustness of transient voltage suppression diode
Five transient voltage suppression (TVS) diodes with breakdown voltages (BV) of 6, 7, 11, 13 and 15 V have been developed using low-temperature (LT) epitaxy technology and an LT fabrication process. The electrostatic discharge (ESD) performance and temperature dependency of reverse leakage current are investigated by applying the IEC61000-4-2 (IEC) standard and an I-V-T analysis. The TVS diodes exhibited excellent ESD robustness, exceeding the standard ESD requirement of IEC level 4, 8 kV in contact discharge, while also maintaining the reverse leakage current level below 10-9 A. Excellent ESD performance was found to be relevant for lower breakdown voltage TVS diodes. The reverse leakage currents showed substantial changes in thermal activation energy from 0.43 to 0.6 eV with respect to BV control from 6 to 15 V. The increased activation energy at high BV was attributed to the transition of the conduction mechanism from tunneling mode to generation-recombination mode. The reduction of reverse leakage current from a generation-recombination to tunneling conduction mechanism is expected to improve the ESD performance of TVS diodes.