Atomic-scale mechanism unlocks thermal-stable high-κ performance in HfO<sub>2</sub> via coherent interfaces.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41545345.
- Also identified by DOI 10.1038/s41467-026-68496-z and PMC identifier 12916799.
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Abstract
Complementary-metal-oxide-semiconductor-compatible HfO<sub>2</sub>-based high-κ dielectrics are pivotal for next-generation electronics in the post-Moore's Law era. However, establishing coherent interfaces via morphotropic phase boundaries across the tetragonal and orthorhombic (ferroelectric or antiferroelectric) phases-a key strategy for enhancing dielectric properties-remains challenging due to unclear atomic-scale mechanisms and inherent thermal instability, which compromises long-term stability and reliability. To address this, we leverage metallurgical quenching principles to stabilize tetragonal/orthorhombic-antiferroelectric morphotropic phase boundaries in HfO<sub>2</sub>-based (Lu:Hf<sub>0.6</sub>Zr<sub>0.4</sub>O<sub>2</sub>) bulk crystals. Through precise composition tuning and growth optimization, we stabilize these metastable morphotropic phase boundaries at the tetragonal/orthorhombic-antiferroelectric interface at room temperature, achieving a comparable κ-value (57) to actively studied tetragonal/orthorhombic-ferroelectric counterparts. Microstructural characterization reveals how tensile strain within the t-phase drives dielectric enhancement through softening of the low-frequency E<sub>u</sub> phonon mode. Critically, the tetragonal/orthorhombic-antiferroelectric morphotropic phase boundary demonstrates a ~58% reduction in κ variation rate over 30-200 °C relative to tetragonal/orthorhombic-ferroelectric counterparts, signifying superior thermal stability. Our study establishes a generalizable design paradigm for developing high-κ dielectrics in fluorite-structured materials, advancing next-generation complementary-metal-oxide-semiconductor-compatible-integrated functional devices for data storage, energy harvesting, sensing, and integrated photonics.