Physical and electrical characterization of Ce-HfO2 thin films deposited by thermal atomic layer deposition

摘要

This paper describes the deposition and characterization of Ce-modified HfO2 thin films. Layers were deposited on Si(100) substrates by thermal atomic layer deposition using (MeCp)2Hf(OMe)(Me), Ce(mmp)4, and H2O as the precursors. Spectroscopic ellipsometry and medium energy ion scattering were used to measure the thicknesses and compositions of the deposited films. After postdeposition annealing, a metastable cubic phase is found to be stabilized in the films. Capacitance–voltage measurements have been used to characterize the dielectric properties of deposited films before and after two annealing regimes. The equivalent oxide thickness of an as-deposited sample with nominal high-κ dielectric thickness of 6 nm is circa 2.8 nm from which the dielectric constant 31 was calculated. The leakage current density is in order of 10−6 A/cm2 at ±1 V. The fabrication of Ce-HfO2 films without plasma or O3-based atomic layer deposition represents a potentially useful manufacturing route for future scaled devices.