Fermi-level unpinning in Pt/Al₂O₃/GaSb PMOS capacitors by sulphurization and rapid thermal annealing of GaSb surfaces

Abstract

A facile route to mitigate the Fermi-level pinning between a p-type GaSb semiconductor and an Al2O3 dielectric is proposed. Combination of the sulphurization of the GaSb surface and the subsequent rapid thermal annealing allowed for high quality GaSb/Al2O3 interfacial characteristics; the interfacial trap density value was <= 2.0 x 10(12) cm(-2) eV(-1) in an energy range of 0.05 <= E-T - E-v <= 0.45 eV for the PMOS capacitor via rapid thermal annealing at 575 degrees C. A physical rationale was given on the basis of the thermo-chemical conversion of Ga2O into Ga2O3 and the conformal elimination of Sb related elements and oxides on the GaSb surface.