A diodelike conduction model for the postbreakdown current in metal-oxide-semiconductor structures

The postbreakdown current in metal-oxide-semiconductor structures with ultrathin silicon dioxide layers is investigated within the framework of a diodelike conduction model with high series resistance. The diodelike behavior is ascribed to the contact effect between the semiconductor electrodes, and the series resistance is mainly attributed to the crowding of the current lines or funneling of the energy states at the constriction which represents the breakdown path. It is shown how this model is able to capture some distinctive features exhibited by the normalized differential conductance and how the model parameters can be extracted from the experimental characteristics without invoking the solution of the generalized diode equation. © 2004 American Institute ofPhysics.