Characterization of HfOxNy thin film formation by in-situ plasma enhanced atomic layer deposition using NH3 and N2 plasmas

The structural and electrical characteristics of in-situ nitrogen-incorporated plasma enhanced atomic layer deposition (PE-ALD) HfOxNy thin films using NH3 and N2 plasmas as reactants were comparatively studied. The HfOxNy test structures prepared using NH3 and N2 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 N2 plasmas, the nitrogen-incorporated HfOxNy 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 N2 plasmas caused by lowering the energy bandgap and band offset are related to the HfN bond ratio and dielectric constant.