Characteristics of a new type of antifuse device that has the MOS structure with a metal oxide high-
kgate dielectric on a p-type Si have been investigated. Different from other antifuses, the on-set of the new device is determined by the breakdown voltage that is adjustable with the thickness or material properties of the high- kstack. A high current ratio of 105 between the programed and unprogrammed states was achieved. This device also behaves like a diode that allows the current to flow in one direction but not the opposite direction. The new device is fabricated from IC processes and materials. It is applicable to various products.