Cubic HfO2 doped with Y2O3 epitaxial films on GaAs(001) of enhanced dielectric constant

摘要

[[abstract]]Nanometer thick cubic HfO2 doped with 19 at. % Y2O3 (YDH) epitaxial films were grown on GaAs (001) using molecular beam epitaxy. Structural studies determined the epitaxial orientation relationships between the cubic YDH films and GaAs to be (001)(GaAs)//(001)(YDH) and [100](GaAs)//[100](YDH). The YDH structure is strain relaxed with a lattice constant of 0.5122 nm with a small mosaic spread of 0.023 degrees and a twist angle of 2.9 degrees. The YDH/GaAs interface is atomically abrupt without evidence of reacted interfacial layers. From C-V and I-V measurements a 7.7 nm thick YDH film has an enhanced dielectric constant kappa similar to 32, an equivalent oxide thickness of similar to 0.94 nm, an interfacial state density D-it similar to 7x10(12) cm(-2) eV(-1), and a low leakage current density of 6x10(-5) A/cm(2) at 1 V gate bias. (c) 2007 American Institute of Physics.