Interface Between Atomic Layer Deposition Ta2O5 Films and GaAs(100) Surfaces

Ta2O5 films were deposited on GaAs(100) surfaces using thermal atomic layer deposition from pentakis dimethyl amino tantalum (PDMAT) and H2O. The interface between the films and native oxide covered GaAs surfaces has been examined using X-ray photoelectron spectroscopy as a function of film thickness and for deposition temperatures ranging from 200 to 350 °C. Gradual removal of the surface arsenic and gallium oxides was observed, with the removal of the arsenic oxides in general more efficient. The high oxidation states of both the arsenic and the gallium oxides were also found easier to remove. Elevation of the process temperature above 300 °C resulted in significant enhancement of the native oxide removal rate. When films were deposited on GaAs surfaces that had the surface oxides removed, a practically sharp interface between the film and the GaAs substrate was maintained.