Theory of "current-ratio" method for oxide reliability: proposal and validation of a new class two-dimensional breakdown-spot characterization techniques

A theory of the current-ratio technique, which is widely used to locate gate oxide breakdown spots in one dimension (i.e., distance from source or drain), is proposed and verified. The theory shows that the current-ratio method is a special case of generalized van der Pauw technique, and as such, can easily be generalized to locate oxide breakdown spots in two dimensions. We develop the theoretical framework of this new class of breakdown-spot characterization techniques and then validate the theory by experiments. We conclude by discussing the implications of locating breakdown spots in two dimensions for reliability projections of ultra-thin gate oxides