Thermal stability of electrical and structural properties of GaAs-based metal-oxide-semiconductor capacitors with an amorphous LaAlO3 gate oxide

We report on thermal stability of the electrical and structural properties of metal-oxide-semiconductor capacitors with amorphous LaAlO3 high dielectric constant (high k) oxide on GaAs epitaxial layers with and without an interface amorphous silicon (a-Si) passivation layer to prevent Fermi level pinning at the III-V/high-k interface. The electrical properties of a-Si passivated GaAs improved with annealing temperature, demonstrating reduced equivalent oxide thickness, small (∼50mV) hysteresis of capacitance-voltage characteristics, and low interface state density (⩽2×1011eV−1cm−2). Transmission electron microscopy with x-ray microanalysis revealed densification of the amorphous LaAlO3 and its reaction with an oxidized a-Si layer.