Properties of HftaxOy high-k layers deposited by ALCVD

HfTa x O y high-k dielectric layers with different compositions were deposited using ALCVD on Si (100) with a SiON surface and annealed after metallization in N 2 using Rapid Thermal Processing (RTP). Physical properties of the as-deposited and annealed blanket layers were studied with Spectroscopic Ellipsometry (SE), X-ray Photoelectron Spectroscopy (XPS), Electron Probe Microanalysis (EPMA), Transition Microscopy (TEM), and X-ray Diffraction (XRD). Electrical behavior of the dielectric layers was analyzed by using C-V and I-V characteristics of MOS capacitors. It is demonstrated that the ALCVD yields uniform oxide layers with controllable compositions. The k-value and the leakage currents depend strongly on the composition, morphology, and crystalline phase of the layers.