Comparision of in situ spectroscopic ellipsometer and ex situ x-ray photoelectron spectroscopy depth profiling analysis of HfO₂/Hf/Si multilayer structure

Abstract

A HfO 2 film was grown by RF magnetron sputtering technique on a Si substrate Using in situ Spectroscopic Ellipsometry (SE), the film thickness and refractive index were examined as a function of deposition time. Ex situ x-ray Photoelectron Spectroscopy (XPS) was used in depth profile mode to determine the phase evolution of HfO 2 /Hf/Si multilayer structure after the growth process. The chemical composition and the crystal structure of the film were investigated by Fourier Transform Infrared (FTIR) spectroscopic measurements and x-ray Diffraction in Grazing Incidence (GI-XRD) mode, respectively. The results showed that the film was grown in the form of HfO 2 film. According to SE analysis, reactive deposition of HfO 2 directly on Hf/Si results to SiO 2 interface of about 2 nm. The final HfO 2 films thickness is 5.4 nm. After a certain period of time, the XPS depth profile revealed that the film was in the form of Hf-rich Hf silicate with SiO 2 interfacial layer. In reference to XPS quantification analysis from top to bottom of film, the atomic concentration of Hf element reduces from 19.35% to 7.13%, whereas Si concentration increases from 22.99% to 74.89%. The phase change of HfO 2 film with time is discussed in details. RECEIVED

Effect of oxide and interface traps on electrical characteristics of post-deposition annealed HfSiO4/n-Si structures

“…Therefore, the peaks centered in the energy ranges of 17.39-19.44 eV and 19.03-21.07 eV in the Hf 4f core-level spectra are assigned to Hf-O-Hf or Hf-O-Si bonds (Hf-O-M) of of Hf 7/2 and Hf 5/2 , respectively. The 4f 7/2 and 4f 5/2 energy states separated from each other with a spin-orbit splitting energy values: 1.69 ± 0.02 eV for RT, 1.65 ± 0.01 eV for 300 • C and 700 • C, 1.67 ± 0.02 eV for [30][31][32][33][34][35]. The peaks in the second level represent to Hf-M bonds (Hf-Hf or Hf-Si) located at ∼14.3 eV (Hf 7/2 ) and ∼16.0 eV (Hf 5/2 ).…”