Si-compatible candidates for high-K dielectrics with the Pbnm perovskite structure

TL;DR

This study combines experimental and first-principles theoretical analyses to evaluate the dielectric properties and structures of Pbnm perovskites, identifying promising Si-compatible high-K dielectric candidates.

Contribution

It provides a comprehensive analysis of the dielectric tensor, structure, and phonon modes of Pbnm perovskites, highlighting new promising candidates for high-K dielectrics on silicon.

Findings

CaZrO_3, SrZrO_3, LaHoO_3, and LaYO_3 are promising high-K dielectric candidates.

Structural and dielectric anisotropies are correlated in these compounds.

Phonon frequencies and infrared activities are characterized for these materials.

Abstract

We analyze both experimentally (where possible) and theoretically from first-principles the dielectric tensor components and crystal structure of five classes of Pbnm perovskites. All of these materials are believed to be stable on silicon and are therefore promising candidates for high-K dielectrics. We also analyze the structure of these materials with various simple models, decompose the lattice contribution to the dielectric tensor into force constant matrix eigenmode contributions, explore a peculiar correlation between structural and dielectric anisotropies in these compounds and give phonon frequencies and infrared activities of those modes that are infrared-active. We find that CaZrO_3, SrZrO_3, LaHoO_3, and LaYO_3 are among the most promising candidates for high-K dielectrics among the compounds we considered.