Low interface state density and low leakage current of atomic‐layer deposited TiO2/Al2O3/sulfur‐treated GaAs

Abstract

AbstractThe (NH4)2S treatment can reduce native oxides and passivate GaAs. Atomic‐layer‐deposited (ALD‐Al2O3) can further remove the residue native oxides by self‐cleaning. For the first time, native oxides can be sufficiently removed by the combination of (NH4)2S treatment and ALD‐Al2O3. Stacked with high dielectric constant TiO2 prepared by atomic‐layer deposition on a Al2O3/(NH4)2S‐treated GaAs MOS capacitor, the leakage current densities can reach 1.9 × 10−8 and 3.1 × 10−6 A/cm2 at ±2 MV/cm. The dielectric constant is 25 and the interface state density is about 2.4 × 1011 cm−2 eV−1.