Fabrication of Y Doped HfO₂ Epitaxial Films Directly on (001) Si Substrate

Abstract

Discovery of ferroelectric behavior of HfO₂-based thin film is attracting much attention as a material applicable to FeFET based on the non-destructive operation with low power consumption and which obeys the scaling rule. For application to FeFET it is an important to grow orthorhombic HfO₂ directly on Si substrate without buffer layer. In this paper, the crystal structure and the growth process of HfO₂:Y epitaxial films on (001) Si substrate by pulsed laser deposition method are discussed. The effect of the O₂ gas pressure and laser power for ablation on the crystal structure, the lattice parameters and the growth process are studied. It is revealed that the epitaxial HfO₂:Y films can be obtained by controlling the oxygen pressure before deposition and active O* species in plume during deposition.