Correlation between Ga-0 signature and midgap states at the AI_2O_3/In_(0.53)Ga_(0.47)As interface

摘要

AI_2O_3/In_(0.53)Ga_(0.47)As gate stacks were fabricated using different concentrations of NH_4OH as a pre-deposition treatment. Increased NH_4OH concentrations significantly reduced the C-V weak inversion hump and the measured near midgap interface states density (D_(it)). X-ray photoelectron spectroscopy (XPS) studies revealed that these changes in the electrical properties were accompanied by a reduction in the amount of the Ga-0 bonding while As-As dimers as well as other XPS detected InGaAs surface species did not correlate with the observed D_(it) trend. Possible explanations for these findings are suggested.