A new pad-oriented multiple-mode ESD protection structure and layout optimization

This work reports a new multiple-mode pad-oriented electrostatic discharge (ESD) protection structure, which protects input-output pads against ESD pulses of all modes. A unique pad-based quasi-symmetric layout design is devised to improve ESD robustness. The new ESD structure features tunable triggering voltage, low holding voltage, low on-impedance, low leakage (/spl sim/pA), fast response time (/spl sim/0.18 ns), and low parasitic effect. It can be placed under a bond pad and consumes little silicon. It passed 14 kV human body model and 15 kV air-gap International Electrotechnical Commission ESD zapping. It was demonstrated in commercial BiCMOS processes and is suitable for multiple-supply mixed-signal, parasitic-sensitive RF and high-pin-count ICs.