Reliability Characteristics of W/WN/TaO[sub x]N[sub y]/SiO[sub 2]/Si Metal Oxide Semiconductor Capacitors

We investigated the effects of post-gate anneal and WN sputtering power on the gate dielectric integrity of metal oxide semiconductor (MOS) capacitors. The process damage induced by physical vapor deposited metal gates in the high-permittivity (k) gate dielectric was partially relieved by a post-gate anneal. This is manifested by reduced leakage current, higher wear-out breakdown voltage, reduced charge trapping, and improved interface characteristics such as reduced hysteresis and interface state density We observed a noticeable increase of charge trapping and interfacial roughness at the interface with WN power density while the level remained similar. Degradation in the reliability characteristics with sputtering power density might be attributed to irrecoverable damage in the film.