Interfacial self-Cleaning during PEALD HfO₂ process on GaAs using TDMAH/O₂ with different (NH₄)₂S cleaning time

This study presents an examination of the interfacial and electrical properties of HfO₂ films grown by plasma-enhanced atomic layer deposition with tetrakis(diethylmethylamino) hafnium and O₂ precursors on GaAs substrates cleaned with HF and then (NH₄) ₂S cleaning for three different dipping times. Systematic X-ray photoelectron spectroscopy analyses both before and after the HfO₂ deposition revealed that the optimal cleaning time in terms of the removal of the As- and Ga-oxides was significantly reduced by the partial self-cleaning process that occurred at a substantially lower deposition temperature of only 200C, possibly due to the plasma effect. The frequency dispersion characteristics were strongly dependent on the cleaning method, however, the hysteresis characteristics were not.