Chemical structures and electrical properties of atomic layer deposited HfO2 thin films grown at an extremely low temperature (≤100 °C) using O3 as an oxygen source

Abstract The properties of atomic layer deposited (ALD) HfO 2 films grown at low temperatures (≤100 °C) were examined for potential applications in flexible display and bioelectronics. A saturated ALD growth behavior was observed even at an extremely low temperature (30 °C) due to the strong oxidizing potential of O 3 . However, HfO 2 films grown at low temperatures showed a low film density and high impurity concentration, because the thermal energy during film growth was insufficient to remove ligands completely from Hf ions in precursor molecule. This resulted in low dielectric constant and high leakage current density of the films. Nevertheless, HfO 2 film grown at 100 °C using O 3 gas with a high concentration (390 g/Nm 3 ) showed a tolerable impurity concentration with the dielectric constant of ∼16 and breakdown field of ∼4 MV/cm, which are approximately two-thirds of those of HfO 2 film grown at 250 °C.