Paper TF-TuP5
Effect of Temperature on the Native Oxide Consumption during the ALD of Ta₂O₅ and TiO₂ on GaAs (100) Surfaces

Tuesday, November 1, 2011, 6:00 pm, Room East Exhibit Hall

Thermal ALD processes for the deposition of TiO₂ and Ta₂O₅ have been developed using amide precursors and H₂O as reagents. The TiO₂ films were deposited from tetrakis dimethyl amido titanium and H₂O and the Ta₂O₅ films were deposited from pentakis dimethyl amido tantalum and H₂O. The growth rate for both processes was ~0.6 Å/cycle at 200°C and 250°C respectively. These temperatures represent the so-called ALD minimum. At these temperatures the existence of a reaction that leads to the consumption of the surface native oxides during depositions on GaAs (100) surfaces has been confirmed using x-ray photoelectron spectroscopy and high resolution transmission electron microscopy. To investigate the effect of temperature on the native oxide consumption rate two sets of samples with thickness 2 and 3 nm have been prepared at temperatures ranging from 100 to 350°C. For both ALD chemistries a significant enhancement in the gallium and arsenic oxide consumption rate was observed for process temperatures above 300°C. For depositions performed at temperatures more than 50°C below the ALD minimum the consumption reaction is significantly slower.