LAUSR

The electrical, structural, and chemical properties of HfO2/Al2O3/GaSb metal-oxide-semiconductor capacitors (MOSCAPs) fabricated on Sb-rich (2 × 5) and Sb-stabilized (1 × 3) surfaces by atomic layer deposition are characterized. A combination of the transmission electron microscopic, x-ray photoelectron spectroscopic, and atomic force microscopic observations shows that the Sb-rich surface, with its excessive Sb atoms and clusters, leads to island deposition of the dielectric materials and results in the high leakage current of the MOSCAPs. For the MOSCAPs fabricated on the Sb-stabilized (1 × 3) surface, a density of interface traps as low as 8.03 × 1011 cm−2 eV−1 near the valence band and 1.86 × 1012 cm−2 eV−1 at the midgap is obtained as estimated by the conductance method.