The structural and electrical characteristics of in-situ nitrogen-incorporated plasma enhanced atomic layer deposition (PE-ALD) HfOxNy thin films using NH3 and N-2 plasmas as reactants were comparatively studied. The HfOxNy test structures prepared using NH3 and N-2 plasmas were analyzed by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and high resolution transmission electron microscopy (HR-TEM) to investigate the chemical composition, crystallinity, and cross-sectional layers including the interfacial layer, respectively. By utilizing NH3 and N-2 plasmas, the nitrogen-incorporated HfO,N), thin films fabricated by in-situ PE-ALD showed a high dielectric constant and thermal stability, which suppresses the interfacial layer and increases the crystallization temperature. The high leakage current densities of the HfOxNy thin film test structures fabricated using NH3 and N-2 plasmas caused by lowering the energy bandgap and band offset are related to the Hf-N bond ratio and dielectric constant. 2015 Elsevier B.V. All rights reserved.