1. A fuse structure comprising: a substrate; a gate dielectric formed on the substrate; a gate electrode formed on the gate dielectric; and first and second source/drain regions formed on the substrate on opposite sides with respect to the gate electrode; wherein the first and second source/drain regions and gate electrode correspond to a transistor; and wherein the gate dielectric is configured such that a plurality of oxygen vacancies trapping respective charges are formed within the gate dielectric upon application of a pulse to the gate electrode; wherein the pulse is applied to the gate electrode while maintaining a source voltage and a drain voltage at constant levels; wherein a magnitude of the pulse applied to the gate electrode is negative relative to the source voltage; and wherein the application of the pulse to the gate electrode permanently changes a threshold voltage (V t ) of the transistor.