Electrical properties of atomic layer deposited HfO2 gate dielectric film using D2O as oxidant for improved reliability

The initial performance And reliability characteristics of metal-oxide-semiconductor (MOS) capacitors with HfO2 films deposited with H2O or D2O as an oxidant and Hf[N(C2H5)(CH3)](4) as a metal precursor using atomic layer deposition (ALD) were investigated. From secondary ion mass spectroscopy (SIMS) analysis, we observed that deuterium was homogeneously incorporated into the HfO2 film using D2O during ALD. Compared with H2O-processed devices, D2O-processed devices exhibit less charge trapping, less interface trap density generation, and longer time-dependent dielectric breakdown (TDDB) under electrical stress. This improvement of reliability characteristics can be explained by the deuterium isotope effect, which leads to a larger bonding strength of deuterium in the HfO2 film and at the HfO2/Si interface.