High-k properties of atomic-layer-deposited HfO2 films using a nitrogen-containing Hf[N(CH3)2]4 precursor and H2O oxidant

HfO2 thin films were deposited on HF-dipped Si wafers at 300 degreesC using an atomic-layer-deposition technique with N-containing Hf[N(CH3)(2)](4) and H2O as the precursor and oxidant, respectively. A thin interfacial SiNx layer was spontaneously formed at the HfO2/Si interface during film growth. This interfacial SiNx layer prevented substrate Si diffusion into the HfO2 film. Therefore, the reduction in the capacitance density as a result of post-annealing at 800 degreesC was minimized. The leakage current density was also reduced due to the more amorphous-like structure of the film. Furthermore, the interfacial trap density (D-it) of <5x10(10) cm(-2) eV(-1) near the midgap energy states was obtained from an as-deposited film that has a capacitance equivalent thickness of 1.8 nm. This D-it value was comparable to that of the well-grown SiO2/Si interface. However, the D-it slightly increased after post-annealing as a result of the increased N concentration at the interface, but it was still <1x10(11) cm(-2) eV(-1). (C) 2003 American Institute of Physics.