A semiconductor die is described. This semiconductor die includes an electro-static discharge (ESD) device with a metal component coupled to an input-output (I/O) pad, and coupled to a ground voltage via a signal line. Moreover, adjacent edges of the metal component and the I/O pad are separated by a spacing that defines an ESD gap. When a field-emission or ionization current flows across the ESD gap, the metal component provides a discharge path to the ground voltage for transient ESD signals. Furthermore, the ESD gap is at least partially enclosed so that there is gas in the ESD gap.