I-PEX Inc. (Headquarters: Shimogyo-ku, Kyoto; Representative Director and President: Reiji Konishi; hereinafter referred to as I-PEX) announces that its group company, I-PEX Piezo Solutions Inc. (Headquarters: Ube City, Yamaguchi Prefecture; CEO: Kenji Ogata; hereinafter referred to as I-PEX Piezo Solutions), has achieved a breakthrough in a joint study with Osaka University. Using I-PEX Piezo Solutions' Si KRYSTAL® Wafer—a silicon substrate with a Pt/ZrO₂ buffer layer—the research team successfully grew a high-quality LaNiO₃ thin film, a strongly correlated oxide, on a silicon substrate. This technology enables the reversible control of thermal conductivity through 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 core technology for thermal transistors and thermal management in 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.
Overview of the Technology
In this study, we successfully achieved epitaxial growth of LaNiO₃ on a conventional Si substrate by using the Pt/ZrO₂ buffer layer of KRYSTAL® Wafer. The crystallinity reached a level comparable to that of single-crystal substrates, and we have experimentally confirmed that high thermal switching performance, previously not expected with on 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, effectively 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 with mass production and practical application: Can be integrated into existing semiconductor manufacturing processes, offering significant business value in terms of cost reduction and scalability.
About I-PEX Piezo Solutions Inc.
I-PEX Piezo Solutions Inc. was established as an independent piezoelectric MEMS foundry, formed from I-PEX Group's piezoelectric MEMS processing division. By combining this expertise with advanced single-crystal piezoelectric thin film deposition technology, the company offers integrated capabilities in both high-performance thin film deposition and piezoelectric MEMS processing technologies.
