Evidence that Fowler-Nordheim field emission contributes significantly
to the device current passing through electroformed metal-insulator-m
etal (MIM) devices at high voltage has been found by recording the low
temperature current-voltage characteristics of Cu-SiOx-Cu devices, At
low voltages (< 10 V) the conduction can be modelled by mechanisms in
which, after emission from a given trap, the carriers are captured by
the next trap in the filament chain (i.e., either 1-dimensional Poole
-Frenkel conduction or tunnelling between adjacent traps). However, at
higher voltages (10-15 V), we find evidence of an additional conducti
on mechanism, Fowler-Nordheim field emission. The onset of this mechan
ism coincides with the onset of electron emission, most of which occur
s at near ballistic energies, indicating that a small fraction of this
current is capable of traversing the remainder of the insulator and t
he top metal layer without significant energy loss.