XPS and spectroscopic ellipsometry studies of HfO₂/Si interface

HfO₂ thin films are deposited on silicon substrate by thermal atomic layer deposition. The change in HfO₂/Si interface is investigated with annealing time. The samples are annealed in N2 ambient at 400°C for 5 and 10 min using RTP. The surface and interface properties are extracted using X-ray Photoelectron Spectroscopy (XPS) Technique and Variable Angle Spectroscopic Ellipsome-try (VASE) is used to determine film thickness. XPS spectra reveal a thin Hafnium Silicate layer is observed in as-deposited sample. The total thickness of the film increased on annealing which indicates growth of interfacial layer with increasing annealing time and XPS spectra confirms SiO₂ layer formation in addition to restructuring of Hafnium Silicate layer. (author)