Interface state Density and Barrier Height Improvement in Ammonium Sulfide Treated Si/Al2O3 Interfaces

Abstract The HF treatment removes the native oxide and lays behind the dangling bonds over the Si surface which causes the increment in density of interface traps (Dit) through the direct deposition of high-k dielectric on Si. Here, we propose the facile method for reduction of interface traps and improvement in barrier height with the (NH4)2S treatment on Al2O3/Si interfaces, which can be used as the base for the non-volatile memory device. The AFM was used to optimize the treatment time and surface properties, while XPS measurements were carried out to study the interface and extract the barrier height (ΦB). The short period of 20 s treatment shows the improvement in the barrier height (1.02 eV), while the one order reduction in the Dit (0.84 × 1012 cm2/eV) of sulfur passivated Al/Al2O3/Si MOS device. The results indicate the favorable passivation of the dangling bonds over the Si surfaces covered by sulfur atoms.