An eFuse begins with a single crystal silicon-on-insulator (SOI) structure that has a single crystal silicon layer on a first insulator layer. The single crystal silicon layer is patterned into a strip. Before or after the patterning, the single crystal silicon layer is doped with one or more impurities. At least an upper portion of the single crystal silicon layer is then silicided to form a silicided strip. In one embodiment the entire single crystal silicon strip is silicided to create a silicide strip. Second insulator(s) is/are formed on the silicide strip, so as to isolate the silicided strip from surrounding structures. Before or after forming the second insulators, the method forms electrical contacts through the second insulators to ends of the silicided strip. By utilizing a single crystal silicon strip, any form of semiconductor, such as a diode, conductor, insulator, transistor, etc. can form the underlying portion of the fuse structure. The overlying silicide material allows the fuse to act as a conductor in its unprogrammed state. However, contrary to metal or polysilicon based eFuses which only comprise an insulator in the programmed state, when the inventive eFuse is programmed (and the silicide is moved or broken) the underlying semiconductor structure operates as an active semiconductor device.