Effects of HCI treatment and predeposition vacuum annealing on Al_2O_3/GaSb/GaAs metal-oxide-semiconductor structures

摘要

The effects of HCI treatment and predeposition vacuum annealing (VA) on n-type GaSb/GaAs metal-oxide-semiconductor (MOS) structures with the atomic layer deposition (ALD) of Al_2O_3 dielectrics are studied. We obtained MOS structures with good Fermi level modulation by HCI treatment prior to the deposition of Al_2O_3. From X-ray photoelectfon spectroscopy (XPS) analysis, we found that the Ga_2O_3 content increases during the Al_2O_3 deposition, whereas the amounts of Sb components are reduced. The excess growth of Ga_2O_3 is inhibited by the reductions in the amounts of Sb components by the HCI treatment. Further reductions in the amounts of Sb components are observed following predeposition VA, indicating a lower density of states (D_(it)). However, the frequency dispersion in the capacitance-voltage (C-V) characteristics Increases with predeposition VA at higher temperatures.