Phase Stabilization of Al:HfO₂ Grown on In_<i>x</i>Ga_1–<i>x</i>As Substrates (<i>x</i> = 0, 0.15, 0.53) via Trimethylaluminum-Based Atomic Layer Deposition

Al:HfO₂ is grown on III–V compound substrates by atomic layer deposition after an in situ trimethylaluminum-based preconditioning treatment of the III–V surface. After post-deposition rapid thermal annealing at 700 °C, the cubic/tetragonal crystalline phase is stabilized and the chemical composition of the stack is preserved. The observed structural evolution of Al:HfO₂ on preconditioned III–V substrates shows that the in-diffusion of semiconductor species from the substrate through the oxide is inhibited. Al-induced stabilization of the Al:HfO₂ crystal polymorphs up to 700 °C can be used as a permittivity booster methodology with possibly important implications in the stack scaling issues of high-mobility III–V based logic applications

A Novel Sb₂Te₃ Polymorph Stable at the Nanoscale

We report on the MOCVD synthesis of Sb₂Te₃ nanowires that self-assemble in a novel metastable polymorph. The nanowires crystallize in a primitive trigonal lattice (<i>P</i>3̅<i>m</i>1 SG #164) with lattice parameters <i>a</i> = <i>b</i> = 0.422 nm, and <i>c</i> = 1.06 nm. The stability of the polymorph has been studied by first principle calculations: it has been demonstrated that the stabilization is due to the particular side-wall faceting, finding excellent agreement with the experimental observations