Investigation of HfN_x-based films by Rutherford backscattering spectrometry and X-ray reflectometry

HfN_x-based films on SiO₂/Si stack were grown by metal organic chemical vapor deposition (MOCVD) using tetrakis-diethylamido hafnium (TDEAHf) precursor and one of them was subsequently ex-situ annealed at an elevated temperature. The structural parameters of HfN_x-based films, for the as-grown and the post-growth annealing samples, were characterized by Rutherford backscattering spectrometry (RBS), X-ray reflectometry (XRR), and atomic force microscopy (AFM). The RBS analysis of the post-growth annealing sample demonstrated that the N:Hf ratio of HfN_x-based films decreases with an increase in depth. The XRR results also indicated that the N:Hf ratio in the HfN_x-based films for the post-growth annealing sample at the surface was bigger than that located near the SiO₂/Si stack. In addition, the surface root mean square (RMS) roughness of the post-growth annealing sample was also bigger than that of the as-grown sample.