TiW ( N ) as Diffusion Barriers Between Cu and Si

and are employed as diffusion barriers in the Cu/barrier/Si system. The thermal stability of and contacted p + n junction diodes was investigated with respect to metallurgical reaction and electrical characteristics. The as‐deposited film formed body‐centered cubic (bcc) structure, while the film formed face‐centered cubic (fcc) structure. The structure remains intact up to 750°C 30 s rapid thermal anneal (RTA) in ambient; at 775°C, the Cu diffuses through the layer to form with an overlayer of Ti‐W‐Si on the surface. The system is metallurgically stable up to 1000°C 30 s RTA in ambient. The junction diodes were able to withstand the RTA annealing up to 675°C without losing the device integrity; however the devices' characteristics are completely destroyed at temperatures above 775°C inconsistent with the occurrence of dramatic metallurgical reaction. The junction diodes were able to withstand the RTA treatment up to 650°C without electrical characteristic degradation; and the devices' characteristics degrade gradually with the increase of RTA temperature.