I-PEX Inc. (Headquarters: Shimogyo-ku, Kyoto, Japan; Representative Director, President and Executive Officer: Reiji Konishi; hereinafter "I-PEX") announces that its group company, I-PEX Piezo Solutions Inc. (Headquarters: Ube City, Yamaguchi Prefecture, Japan; Representative Director and CEO: Kenji Ogata; hereinafter "I-PEX Piezo Solutions"), in a joint study with Osaka University, has announced that I-PEX Piezo Solutions' Pt/ZrO₂ buffer layer Si KRYSTAL® Wafer, a substrate with Pt/ZrO₂ buffer layer provided by I-PEX Piezo Solutions, has realized a technology to grow high quality LaNiO₃ thin film, a strongly correlated oxide, on a silicon substrate and reversibly control thermal conductivity by electrical manipulation.
The co-authored paper summarizing these research results has been published in the scientific journal "Applied Physics Express" (Vol. 19, No. 3, March 2026), published by the Japan Society of Applied Physics.
High-quality growth of LaNiO₃ thin films on "KRYSTAL® Wafer". (a) Substrate structure. (b) Electron microscope image of a cross-section of the thin film (film thickness approximately 140 nm). (c)(d) X-ray diffraction analysis confirmed that LaNiO₃ was grown on a Si substrate with high crystallinity comparable to that of a single-crystal substrate. (Quoted from the paper)
For more details on the research results and paper, please click here.
background
The technology of electrically controlling thermal conductivity is a crucial foundational technology for thermal management in thermal transistors and next-generation electronics. However, conventionally, growing strongly correlated oxides such as LaNiO₃ with high quality required expensive single-crystal substrates such as LSAT and YSZ, posing significant challenges in terms of cost and productivity for industrial applications.
技術実現の概要
In this study, we successfully achieved epitaxial growth of LaNiO₃ on a common Si substrate by using the Pt/ZrO₂ buffer layer of "KRYSTAL® Wafer". The crystallinity reached a level comparable to that of a single-crystal substrate, and we experimentally confirmed that high thermal switching performance, which was not expected with conventional Si substrates, was achieved.
Main features of this technology
- High-quality epitaxial growth on Si substrates: Achieving high-quality growth of LaNiO₃ thin films on Si substrates, the standard substrate in the semiconductor industry, without using expensive single-crystal substrates.
- Reversible control of thermal conductivity: Thermal conductivity can be turned on and off through electrical manipulation, essentially functioning as a "thermal transistor."
- Crystallinity comparable to single-crystal substrates: The superior epitaxial growth environment of "KRYSTAL® Wafer" enables performance on Si substrates that was previously only achievable with expensive substrates.
- High suitability for mass production and practical application: It can be integrated into existing semiconductor manufacturing processes, offering significant business value in terms of cost reduction and scalability for mass production.
About I-PEX Piezo Solutions Inc.
I-PEX Piezo Solutions Inc. was established as an independent piezoelectric MEMS foundry, possessing high-performance piezoelectric thin film deposition and piezoelectric MEMS processing technologies, by separating the piezoelectric MEMS processing division from the I-PEX Group and integrating it with superior single-crystal piezoelectric thin film deposition technology.
