Figure 1

Temperature dependent Raman spectra of RRAM oxide nanoscale thin films. Raman spectra of crystallized 50 nm thin films of (a) HfO₂ and (b) TiO₂, measured at temperatures ranging from 25 °C to 600 °C. Spectra are vertically offset for clarity. Insets show peak position shift with temperature of a selected mode, error bars represent 95% confidence bounds of Lorentzian peak fitting. The HfO₂ was sputtered onto Pt (50 nm) on sapphire substrate and then annealed at 600 °C for 2 hours. All measured peaks above 110 cm⁻¹ are assigned to monoclinic phase of HfO₂ (as confirmed by XRD)²⁴. The TiO₂ was sputtered onto SiO₂ (90 nm) on Si substrate and annealed at 400 °C for 1 hour. The peak at ~141 cm⁻¹ (25 °C) is assigned to anatase TiO₂ and the other peaks are from the Si substrate.