Interface of atomic layer deposited HfO2 films on GaAs (100) surfaces

Abstract

Hf O 2 films have been deposited by using a tetrakis(dimethylamino)hafnium/H2O atomic layer deposition (ALD) process on GaAs. X-ray photoelectron spectroscopy measurements show that the HF and NH4OH predeposition surface treatment results in efficient removal of the Ga and As native oxides. No interface oxidation is detected after 15cycles of HfO2 ALD implying effective passivation of the GaAs surface. Spectroscopic ellipsometry confirms linear growth at 1.0Å∕cycle on both starting surfaces, while Rutherford backscattering spectrometry indicates steady-state coverage after about 10 ALD cycles. For films grown on native oxide GaAs, complete removal of the As oxide is observed after 20 ALD cycles.