High-kappa dielectrics for insulating layers are a current key ingredient of microelectronics. X(2)O(3) sesquioxide compounds are among the candidates. Here, we show for a typical material of this class, Sc(2)O(3), that the relatively modest dielectric constant of its crystalline phase is enhanced in the amorphous phase by over 40% (from similar to 15 to similar to 22). This is due to the disorder-induced activation of low frequency cation-related modes which are inactive or inefficient in the crystal and by the conservation of effective dynamical charges (a measure of atomic polarizability). The analysis employs density-functional energy-force and perturbation-theory calculations of the dielectric response of amorphous samples generated by pair-potential molecular dynamics. (C) 2008 American Institute of Physics.

Dielectric constant boost in amorphous sesquioxides / Delugas, Pietro Davide; Fiorentini, V; Filippetti, A.. - In: APPLIED PHYSICS LETTERS. - ISSN 0003-6951. - 92:17(2008). [10.1063/1.2917797]

Dielectric constant boost in amorphous sesquioxides

DELUGAS, Pietro Davide;
2008-01-01

Abstract

High-kappa dielectrics for insulating layers are a current key ingredient of microelectronics. X(2)O(3) sesquioxide compounds are among the candidates. Here, we show for a typical material of this class, Sc(2)O(3), that the relatively modest dielectric constant of its crystalline phase is enhanced in the amorphous phase by over 40% (from similar to 15 to similar to 22). This is due to the disorder-induced activation of low frequency cation-related modes which are inactive or inefficient in the crystal and by the conservation of effective dynamical charges (a measure of atomic polarizability). The analysis employs density-functional energy-force and perturbation-theory calculations of the dielectric response of amorphous samples generated by pair-potential molecular dynamics. (C) 2008 American Institute of Physics.
2008
92
17
172903
Delugas, Pietro Davide; Fiorentini, V; Filippetti, A.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/32374
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