High mobility and excellent electrical stability of MOSFETs using a novel HfTaO gate dielectric

In this work, we developed a novel Hf-based gate dielectric for MOSFETs with TaN metal gate. By incorporating Ta into HfO₂ films, significant improvements were achieved in contrast to pure HfO₂: (1) the dielectric crystallization temperature is increased up to 1000°C; (2) interface states density (D_it) is reduced by one order of magnitude; (3) electron peak mobility is enhanced by more than two times; (4) charge trapping and threshold voltage shift is reduced by 20 times, greatly prolonging the device lifetime; (5) negligible sub-threshold swing and G_m variations under constant voltage stress (CVS).