Comparison between atomic-layer-deposited HfO2 films using O3 or H2O oxidant and Hf[N(CH3)2]4 precursor

The dielectric properties of HfO2 thin films, which were deposited on Si wafers by an atomic layer deposition (ALD) technique at a wafer temperature of 300 degreesC using a N-containing, tetrakis dimethylamido hafnium precursor (Hf[N(CH3)(2)](4)), were highly improved by adopting O-3 as the oxidant during the ALD instead of H2O. The films contained a much smaller carbon impurity concentration and were of more amorphous nature compared to the films grown using H2O as oxidant. Temperature-dependent leakage current analysis showed that the films grown using O-3 as oxidant had a higher interfacial potential barrier for tunneling and the leakage current densities of the as-deposited film were three orders of magnitude smaller than that of the films grown using H2O. The dielectric constant of the HfO2 film was 24.4 and the leakage current density was 1.6x10(-7) A/cm(2) when the capacitance equivalent thickness was 1.49 nm. (C) 2004 American Institute of Physics.