Charge transport trough a “metal-thick insulator-metal” structure during impulse voltage excitation

The current-voltage characteristic for a “metal-thick insulator-metal” structure has been investigated using high-voltage pulse excitation. Charge electro-optic mapping has shown a filamentary current distribution, which is in good agreement with the arguments for S- type Negative Differential Resistance during the prebreakdown stages of organic insulators. Based on the experimental data and the obtained I − V curve for the examined MIM structure, a first-order nonlinear equivalent circuit is proposed and its stability criteria are discussed. It appears that impact ionization phenomena are associated with current instabilities between stable and unstable operating points of the equivalent circuit.