An antifuse is disclosed which has an electrically-insulating region sandwiched between two electrodes. The electrically-insulating region has a single layer of a non-hydrogenated silicon-rich (i.e. non-stoichiometric) silicon nitride SiN.sub.X with a nitrogen content X which is generally in the range of 0<X.ltoreq.1.2, and preferably 0.5.ltoreq.X.ltoreq.1.2. The breakdown voltage V.sub.BD for the antifuse can be defined to be as small as a few volts for CMOS applications by controlling the composition and thickness of the SiN.sub.X layer. The SiN.sub.X layer thickness can also be made sufficiently large so that Poole-Frenkel emission will be the primary electrical conduction mechanism in the antifuse. Different types of electrodes are disclosed including electrodes formed of titanium silicide, aluminum and silicon. Arrays of antifuses can also be formed.