\textit{In-situ} XPS, STM and STS analyses of high k oxide/III-V interfaces

The new technology of high-k plus metal gate on high carrier mobility semiconductors like Ge and InGaAs hybrid with Si are urgently pursued for CMOS scaling beyond 15 nm node. The D$_{it}$ distributions of these high k/semiconductor interfaces are generally governed by a peak near the mid-gap, unlike SiO$_{2}$/Si showing a flat D$_{it}$ over the entire energy gap. To remove the mid-gap peak in further reducing D$_{it}$, \textit{in-situ} ALD growth of high k oxides such as Al$_{2}$O$_{3}$, HfO$_{2}$ on various reconstructed In$_{x}$Ga$_{1-x}$As(001) surfaces prepared by molecular beam epitaxiy have been conducted to tailor the interface on the atomic level. The mechanisms of interfacial traps at high-k/III-V heterostructures were investigated by using \textit{in-situ} x-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS), particularly in the initial stage of interfacial reactions. The surface species and chemical bonding configurations responsible for unpinned Fermi level are being determined.