In Situ Study of the Role of Substrate Temperature during Atomic Layer Deposition of HfO2 on InP
Hinkle, Christopher L.
Wallace, Robert M.
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The dependence of the "self cleaning" effect of the substrate oxides on substrate temperature during atomic layer deposition (ALD) of HfO₂ on various chemically treated and native oxide InP (100) substrates is investigated using in situ X-ray photoelectron spectroscopy. The removal of In-oxide is found to be more efficient at higher ALD temperatures. The P oxidation states on native oxide and acid etched samples are seen to change, with the total P-oxide concentration remaining constant, after 10 cycles of ALD HfO₂ at different temperatures. An (NH₄)₂ S treatment is seen to effectively remove native oxides and passivate the InP surfaces independent of substrate temperature studied (200°C, 250°C and 300°C) before and after the ALD process. Density functional theory modeling provides insight into the mechanism of the changes in the P-oxide chemical states.