Effective reduction of interfacial traps in Al2O3/GaAs (001) gate stacks using surface engineering and thermal annealing

摘要

To effectively passivate the technologically important GaAs (001) surfaces, in situ deposition of Al2O3 was carried out with molecular beam epitaxy. The impacts of initial GaAs surface reconstruction and post-deposition annealing have been systematically investigated. The corresponding interfacial state density (D-it) were derived by applying the conductance method at 25 and 150 degrees C on both p-type and n-type GaAs metal-oxide-semiconductor capacitors to establish the D-it spectra in proximity of the critical midgap region. We show that significant reduction of D-it near the midgap is achieved by applying an optimized thermal annealing on samples grown on a Ga-rich (4x6) reconstructed surface. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3488813]