Enabling ultra-high tunability in Ba<sub>1-x</sub>Sr<sub>x</sub>TiO<sub>3</sub> films integrated on silicon

ORAL

Abstract

Achieving high dielectric tunability with stability over broad temperature and frequency ranges is essential for advanced varactors, microwave devices, and telecommunication systems, yet remains challenging. Equally critical, but difficult, is integrating such materials with silicon for scalable applications. Here, we develop high-quality, lead-free Ba₁₋ₓSrₓTiO₃ (BST; x = 0.2–0.8) thin films. By tuning composition, thickness, and strain, we realize a coexistence of cubic, tetragonal, rhombohedral, and orthorhombic phases, forming an MPB-like state. This structural interplay yields exceptional dielectric properties, including ultra-high tunability (~91%) and a breakdown field of ~800 kV/cm at room temperature (10 kHz). Effective-Hamiltonian simulations confirm the MPB-like regime and explain enhanced permittivity and tunability. The films also show strong thermal (330–473 K) and frequency (10 kHz–1 MHz) stability, linked to diffuse transitions and relaxor-like behavior. Finally, successful integration on silicon demonstrates scalability and positions BST films as a promising platform for next-generation tunable electronic devices.

Refrences

Jiang, Y. et al. Enabling ultra-low-voltage switching in BaTiO3. Nat Mater 21, 779–785 (2022).

Zhu, X. et al. Recent Progress of (Ba,Sr)TiO3 Thin Films for Tunable Microwave Devices. Journal of ELECTRONIC MATERIALS vol. 32 (2003).

*Central Research Laboratory, Bharat Electronics, Bangalore 560013, India

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Publication: The following manuscript is submitted to advanced materials and we are working on reviewers comments here.

Presenters

  • Garima Kaura

    • Indian Institute of Science

Authors

  • Garima Kaura

    • Indian Institute of Science

  • Lane W. Martin

    • Rice University

  • SUJIT DAS

    • Indian Institute of Science Bengaluru
    • Indian Insititute of Science, Bangalore

  • Venkatraman Gopalan

    • Pennsylvania State University

  • Laurent Bellaiche

    • University of Arkansas

  • Yun-long Tang

    • School of Material Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China

  • Zuhuang Chen

    • School of Materials Science and Engineering, Harbin Institute of Technology, Shenzhen 518055, China

  • Sukriti Mantri

    • Smart Ferroic Materials Center, Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas, 72701, USA

  • Fang Liu

    • School of Material Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China

  • Sankalpa Hazra

    • Pennsylvania State University

  • Shanquan Chen

    • School of Materials Science and Engineering, Harbin Institute of Technology, Shenzhen 518055, China

  • Shanquan Chen

    • School of Materials Science and Engineering, Harbin Institute of Technology, Shenzhen 518055, China

  • Akash Saha

    • Pennsylvania State University

  • Sourav Chowdhury

    • Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
    • PERTA III, DESY

  • Deepak Prajapat

    • Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany

  • Manuel Valvidares

    • ALBA Synchrotron Light Source, E-08290 Cerdanyola del Vallès, Barcelona, Spain

  • Saluru Baba Krupanidhi

    • Materials Research Centre, Indian Institute of Science, Bangalore, 560012, Karnataka, India

  • Basant Roul

    • Central Research Laboratory, Bharat Electronics, Bangalore 560013, India