High-k Oxide Growth on III-V Surfaces: Chemical Bonding and MOSFET Performance

The growth of high-k oxides on III-V surfaces is of vital importance if high-mobility channels are to replace Si in upcoming CMOS technology nodes. Whether these dielectrics are deposited directly on the channel material itself for surface channel devices or on a III-V barrier layer for reduced leakage in buried channel devices, the chemical bonding at these interfaces must be understood to control its impact on transport properties. We have investigated the chemical bonding of ALD deposited high-k oxides (Al2O3, HfO2) on various III-V semiconductors with multiple surface chemical treatments via in-situ, x-ray photoelectron spectroscopy (XPS). A correlation of these interfacial chemical bonds to defect states and device performance of MOS devices fabricated with these same interfaces has been achieved.