Interface Optimization and Modulation of Leakage Current Conduction Mechanism of Yb2O3/GaSb MOS Capacitors with ALD-Driven Laminated Interlayers

In this report, the impact of atomic-layer-deposition-derived different laminated gate stacks on the interface chemistry and electrical performance of Yb2O3/GaSb metal-oxide-semiconductor (MOS) capacitors has been investigated comparatively. X-ray photoelectron spectroscopy measurements and electrical characterization have revealed the existence of less native oxides and elemental Sb at the Yb2O3/Al2O3/GaSb interface, as well as the optimized frequency dispersion and the minimum leakage current density of 2.25 × 10–7 A/cm2. Meanwhile, conductance–voltage analyses are carried out to determinate the distribution of interface-state density (Dit) in the entire GaSb band gap. It has been found that an ultrathin Al2O3 layer prior to Yb2O3 deposition can effectively delay the generation of the interface state, and the lowest Dit value of 8.7 × 1012 cm–2 eV–1 for the Al/Yb2O3/Al2O3/GaSb capacitor has been achieved. The possible carrier conduction mechanisms for GaSb-based MOS capacitors with different laminated structures measured at room temperatures and low temperatures have also been systematically analyzed. All the results have indicated that the Yb2O3/Al2O3/GaSb gate stack is a promising candidate for future GaSb-based metal-oxide-semiconductor field-effect transistor devices.