Energy-band parameters of atomic-layer-deposited Al$_{2}$O$_{3}$ and HfO$_{2}$ on InxGa$_{1-x}$As

X-ray photoelectron spectroscopy (XPS) combined with reflection electron energy loss spectroscopy (REELS) were used to determine the energy-band parameters, valence-band offsets $\Delta $E$_{V}$, conduction-band offsets $\Delta $E$_{C}$, and energy-band gaps E$_{g}$, of the atomic layer deposited (ALD) high k dielectrics of Al$_{2}$O$_{3}$ and HfO$_{2}$ on InxGa$_{1-x}$As (x=0, 0.15, 0.25, and 0.53). Using REELS, Eg values of the ALD-Al$_{2}$O$_{3}$ and -HfO$_{2}$ were estimated to be 6.77 and 5.56 $\pm$0.05 eV, respectively. The $\Delta $E$_{C}$'s and $\Delta $E$_{V}$'s are larger than 1.5 and 2.5 eV, respectively, for all the ALD-oxide/In$_{x}$Ga$_{1-x}$As samples. The $\Delta $Ec values obtained from the HR-XPS and REELS analyses are in good agreement with those estimated from the electrical measurement according to Fowler-Nordheim tunneling. The results are valuable to the understanding and modeling of the III-V high k MOS devices.