A Novel ESD Clamp Based on the VO 2 Insulator-Metal Transition

Protection from electrostatic discharge (ESD) is a continual challenge in semiconductor manufacturing, requiring significant die space for silicon-based rectifiers. On-chip ESD protection requires devices with a voltage-triggered reduction in resistance by orders of magnitude within a nanosecond or less, in order to safely divert current away from sensitive circuits, and which must return to insulating when the ESD event is over. This behaviour is inherent to insulator-metal transition (IMT) materials [1] like vanadium dioxide (VO 2 ), making them candidates for simple, highly compact ESD clamps that are both bipolar and potentially back-end of the line (BEOL) compatible, dealing with ESD events more rapidly and further away from sensitive devices. Here, we demonstrate VO 2 snapback devices as compact ESD clamps and use transmission line pulse (TLP) testing to evaluate their reliability for the first time. We find that they have a snapback voltage which can be easily engineered via device length and are capable of sustaining $> 10\mathrm{A}$ current in the metallic state, yet still return to insulating once an event is over.