The Formation of an Almost Full Atomic Monolayer via Surface Modification by N₂O-Plasma in Atomic Layer Deposition of ZrO₂ Thin Films

Abstract

A technique for improving significantly the atomic layer deposition rate of high-k ZrO2 and HfO2 thin films was developed using a N2O-plasma oxidant. Even though the process showed much higher growth rate, electrical properties of the dielectric films were similar or superior to those of the film using the conventional O2-plasma oxidant. From the results of Auger electron spectroscopy and X-ray photoelectron spectroscopy, it was concluded that the nitric oxide species were temporally adsorbed on the surface during the N2O plasma process and then removed the ligands from the adsorbed metal precursors more effectively, which allowed more precursors to adsorb. In particular, the deposition rate of ZrO2 thin films (∼0.184 nm/cycle) was similar to the full atomic monolayer deposition rate. This phenomenon is expected to be applied to the surface modification of nanostructured materials as well as the improvement in the interface quality of thin films.