Tetragonal Phase in Ge Doped HfO₂ Films on Si Investigated by X-ray Absorption Spectroscopy

Abstract

The stabilization of the tetragonal phase of 5 nm thick HfO 2 films by Ge doping is investigated using x-ray absorption spectroscopy around O and Ge Kedges and by Rutherford backscattering spectrometry. We show that Ge concentrations higher than ~5at.% are not stable during rapid thermal anneal at temperatures as low as 750 o C and that the tetragonal phase of HfO 2 is achieved at this Ge concentration.