Atomic layer deposition of HfO2 thin films using H2O2 as oxidant

Abstract

HfO 2 films were deposited by atomic layer deposition (ALD) using Hf[(C 2 H 5 )(CH 3 )N] 4 and H 2 O 2 at a temperature range of 175-325 °C. The growth per cycle of the HfO 2 films decreased with increasing temperature up to 280 °C and then abruptly increased above 325 °C as a result of the thermal decomposition of the precursor. Although the HfO 2 films grown with H 2 O 2 exhibited slightly higher carbon contents than those grown with H 2 O, the leakage properties of the HfO 2 films grown with H 2 O 2 were superior to those of the HfO 2 films grown with H 2 O. This is because the HfO 2 films grown with H 2 O 2 were fully oxidized as a result of the strong oxidation potential of H 2 O 2 . The use of the ALD process with H 2 O 2 also revealed the conformal growth of HfO 2 films on a SiO 2 hole structure with an aspect ratio of ∼15. This demonstrates that using the ALD process with H 2 O 2 shows great promise for growing robust HfO 2 films.