Abstract
Atomic-layer-deposited (ALD) high κ dielectric Al2O3 film on In0.53Ga0.47As, using Al(CH3)3 (TMA) and H2O as the precursors, was demonstrated low interfacial density of states (Dit) ~ 2.5x1011 by the charge pumping method for the first time after a dopant activation at RTA 650oC in N2. The depth profile of border-trap density in gate dielectric and low densities of bulk trap (Nbt) ~ 7x1019 cm-3 are obtained by the relationship between Qcp and frequency. Low Dit and Nbt represent excellent interfacial property and oxide quality in employing ALD-Al2O3 as gate dielectric on In0.53Ga0.47As. Besides, energy dependence of Dit is extracted with modulating the rise/fall time of gate pulse.The interfacial properties were through understood with the application of charge pumping and HR-TEM. The density of interfacial trap, variation of bulk trap densities, and energy dependence of interfacial trap density were extraction. These evidences might indicate the theory: the intense trap features suggest that the interface between these two oxides contains a significant defect concentration and the origin may have to do with the fact that the Y cation in Y2O3 is trivalent, and the Hf cation in HfO2 is tetravalent, thus, leading to dissimilar charge distributions near the interface as likely sites for defects. In this way, the traps at interface or near interface can be absorbed to the interface between Y2O3 and HfO2, owing to dielectric materials of dissimilar cation valences, which raised an important possibility of tailoring the trap locations in a gate dielectric stack. Maybe, this work, thus, has raised an important possibility of tailoring the trap locations in a gate dielectric stack through multilayering a number of dielectric materials of dissimilar cation valences.