In this paper, a new metal-insulator-metal (MIM) antifuse was fabricated with the high kappa Al2O3 deposited by atomic layer deposition (ALD) as the dielectric. On this high. antifuse structure, the very low on-state resistance was obtained under certain programming conditions. It is the first time that the antifuse on-state resistance has been found decreasing along with the increase of dielectric film thickness, which is attributed to a large current overshoot during breakdown. For the device with a dielectric thickness of 12 nm, very large overshoot current (similar to 60 mA) was observed and extremely low on- state resistance (similar to 10 Omega) was achieved.