Punchthrough transient voltage suppressor for EOS/ESD protection of low-voltage IC's

A silicon transient voltage suppresser (TVS) is presented for off-chip EOS/ESD protection of ICs with supply voltages ranging from 3.3 V down to 1.5 V. The np/sup +/p/sup -/n four-layer TVS operates in punchthrough mode instead of the avalanche mode as in conventional TVS diodes. Performance was investigated by device simulator TMA-MEDICI for several device structure options for ultra-low-voltage EOS/ESD protection.