Abstract: An electrical fuse includes first and second active regions doped with respective first-type and second-type impurities that form a horizontal P/N junction, first and second spaced apart silicide layers on respective portions of the top surfaces of the first and second active regions, and first and second contacts on the respective top surfaces of the first and second silicide layers. When a first reverse voltage that is higher than a threshold voltage is applied to the electrical fuse through the first and second contacts, the P/N junction is broken down by a reverse current flowing between the first and second active regions so that the electrical fuse is rendered conductive in response to a second reverse voltage that is less than the threshold voltage.