Effects of Various Oxidizers on the ZrO₂ Thin Films Deposited by Atomic Layer Deposition

Abstract

In this study, we investigated the effect of O₂ and N₂O as an oxidizer of atomic layer deposition (ALD) using Zr tert-butoxide on the characteristics of ZrO₂ compared to a conventional reactant, H₂O. We observe that deposition temperature lower than 250°C is ALD reaction regime while the temperature higher than 300°C is CVD reaction region. H₂O as an oxidant causes fully crystallization to monoclinic phase, while N₂O and O₂ results in amorphous phase. Leakage current of ZrO₂ films using H₂O shows much higher than those of the films using N₂O and O₂. Compared to conventional H₂O, O₂ and N₂O are suitable for reactant of ALD using Zr-t-butoxide for alternative gate dielectric applications. Through the variation of oxidizers, zirconia thin films which have higher capacity and lower leakage current are fabricated.

Keywords:

• ZrO₂
• ALD
• Zr tert-butoxide
• N₂O
• Gate dielectrics

ACKNOWLEDGMENTS

This work was supported by Korea Research Foundation Grant (KRF-2001-041-E00439).