Abstract: An Electro-Static-Discharge (ESD) protection device has a Fin Field-Effect Transistor (FinFET) with a silicon fin with a step separating a top fin and a bottom fin. The gate wraps around the top fin but not the bottom fin. Normal gate-controlled channel conduction occurs in the top fin between a source and a drain in the top fin. Underneath the conducting channel is a buried conducting region in the bottom fin that conducts after a breakdown voltage is reached during ESD. A ledge, abrupt slope change in the sidewalls of the fin, or a doping increase occurs at the step between the top fin and bottom fin. The bottom fin is 2-3 times wider than the top fin, causing the resistance of the buried conducting region to be 2-3 times less than the resistance of the conducting channel, steering breakdown current away from the channel, reducing failures during breakdown.

Abstract: An Electro-Static-Discharge (ESD) input-protection device has an NPNP structure of a N+ cathode formed in a FINFET fin or highly-doped region over a floating P-well, and a P+ fin or highly-doped region anode formed over a floating N-well that touches the floating P-well. The floating P-well is surrounded by an isolating N-well and has a deep N-well underneath to completely isolate the floating P-well from the p-type substrate. No well taps are formed in the floating wells or in the isolating N-wells. The floating P-well and the floating N-well are thus truly floating at all times. Since the wells are floating, the NPNP structure appears as three junction diodes in series, which has a lower capacitance than a single diode that the NPNP structure would appear as when one of the wells was shorted or biased. During an ESD event the NPNP structure behaves as a single diode.

Abstract: An Electro-Static-Discharge (ESD) protection device has a Fin Field-Effect Transistor (FinFET) with a silicon fin with a step separating a top fin and a bottom fin. The gate wraps around the top fin but not the bottom fin. Normal gate-controlled channel conduction occurs in the top fin between a source and a drain in the top fin. Underneath the conducting channel is a buried conducting region in the bottom fin that conducts after a breakdown voltage is reached during ESD. A ledge, abrupt slope change in the sidewalls of the fin, or a doping increase occurs at the step between the top fin and bottom fin. The bottom fin is 2-3 times wider than the top fin, causing the resistance of the buried conducting region to be 2-3 times less than the resistance of the conducting channel, steering breakdown current away from the channel, reducing failures during breakdown.