Bidirectional Transient Voltage Suppression Diodes for the Protection of High Speed Data Line from Electrostatic Discharge Shocks

Abstract

A bidirectional transient voltage suppression (TVS) diode consisting of specially designed p--n++-p-multi-junctions was developed using low temperature (LT) epitaxy and fabrication processes. Its electrostatic discharge (ESD) performance was investigated using IV, C-V, and various ESD tests including the human body model (HBM), machine model (MM) and IEC 61000-4-2 (IEC) analysis. The symmetrical structure with very sharp and uniform bidirectional multijunctions yields good symmetrical I-V behavior over a wide range of operating temperature of 300 K ? 450 K and low capacitance as 6.9 pF at 1 MHz. In addition, a very thin and heavily doped n++ layer enabled I-V curves steep rise after breakdown without snapback phenomenon, then resulted in small dynamic resistance as 0.2 ;, and leakage current completely suppressed down to pA. Manufactured bidirectional TVS diodes were capable of withstanding ± 4.0 kV of MM and ± 14 kV of IEC, and exceeding ± 8 kV of HBM, while maintaining reliable I-V characteristics. Such an excellent ESD performance of low capacitance and dynamic resistance is attributed to the abruptness and very unique profiles designed very precisely in p-n++p-multi-junctions.