ON-state programming and OFF-state reliability of metal-to-metal antifuse based 10 nm-thick SiNx film for 3.3 V operation

Reliability of newly a developed metal-to-metal antifuse (Al-0.5%Cu/10nm-thick SiNx/amorphous-like WSix) with very low ON-resistance below 10 ohm has been investigated. Sufficient OFF-state reliability can be obtained by using amorphous-like WSix film as a lower electrode, which has a remarkably smooth surface without sharp protrusions. By using Al-Cu film as an upper electrode, low ON-resistance can be easily obtained with a wide range of programming current down to 0.1 mA, which is enough to melt the lower portion of Al-Cu film and to diffuse aluminum into the SiNx film due to joule heating generated at filament. Moreover, favorable electromigration (EM) performance and ON-state stability of the antifuse programmed in plus polarity could be obtained. The result could be attributed to the final state of the filament composed of Al-W-Si, which is formed by a reaction between electromigrated tungsten through ruptured SiNx film and locally melted aluminum just on the ruptured SiNx film due to joule heating.