Conformable formation of high quality ultra-thin amorphous Ta/sub 2/O/sub 5/ gate dielectrics utilizing water assisted deposition (WAD) for sub 50 nm damascene metal gate MOSFETs

A conformable formation process of ultra-thin Ta/sub 2/O/sub 5/ gate dielectrics, which is applicable to 50 nm damascene gate MOSFETs, was developed. Assisted by H/sub 2/O, perfect conformability was successfully realized even in the narrow gate groove (50 nm), while maintaining a low gate leakage. An excellent device performance of S-factor 72 mV/decade was obtained in 90 nm MOSFET with amorphous Ta/sub 2/O/sub 5/ gate dielectrics of T/sub eff/ 1.6 nm.