Failure analysis of titanium nitride/titanium silicide barrier contacts under high current stress

The I-V characteristics of single-pair titanium nitride/titanium silicide contact structures under current ramp are reported to reveal the existence of an unstable region when the current exceeds a critical value beyond which the diffusion region, especially near the pn junction, becomes an intrinsic semiconductor. When stressing at a constant current in this stable region, the devices tend to either become electrically shorted with metal flowing (at room temperature) into the diffusion region/substrate or exhibit a leaky junction (at high temperature) within a very short amount of time, When stressing at a current below the critical value, the devices show damage to anode contacts in the form of either voiding or junction spiking, due to the conventional electromigration mechanism.<>