Mechanism of the sequential interface structures changes in the epitaxial Pt/ZrO₂/Si

We are pleased to announce that our research has been published in the Japanese Journal of Applied Physics, a leading academic journal in the field of applied physics. The paper was led by an I-PEX Piezo Solutions researcher as the first author and was conducted in collaboration with Osaka University and the Nara Institute of Science and Technology (NAIST).

Electronic devices such as smartphones, wearable devices, automobiles, and industrial equipment are an essential part of modern life. Continuous improvements in their performance, miniaturization, and functionality have been enabled by MEMS technology. Among MEMS technologies, piezoelectric materials, which can convert electrical signals into mechanical motion and vice versa, are attracting growing attention for applications including highly sensitive sensors, actuators, and high-frequency communication devices.
However, integrating high-performance piezoelectric materials onto silicon substrates remains a significant challenge. Because piezoelectric materials and silicon have fundamentally different crystal structures and atomic arrangements, achieving high-quality crystal growth is difficult. To address this challenge, I-PEX Piezo Solutions  has been developing a proprietary epitaxial platform technology that utilizes zirconia (ZrO₂) and platinum (Pt) thin films formed on silicon substrates as a foundation for growing functional materials.

In this study, we performed an atomic-scale analysis of the interfaces within a Pt/ZrO₂/Si multilayer structure and clarified the mechanism that enables high-quality crystal growth. The results revealed the formation of an ultra-thin reaction layer at the interface between zirconia and platinum. This layer acts as a “bridge” that accommodates differences in crystal structure between the two materials, enabling high-quality single-crystal thin-film growth even for material combinations that would otherwise be difficult to integrate epitaxially. This achievement provides important technological insight for the practical realization of high-performance MEMS devices based on piezoelectric thin films. Furthermore, I-PEX Piezo Solutions  can provide wafers incorporating this technology on industry-standard 6-inch and 8-inch silicon wafers, demonstrating its potential not only for research and development but also for future high-volume manufacturing applications. (KRYSTAL^® Wafer)

Going forward, we will continue to leverage the knowledge gained through this research to accelerate the development of next-generation devices, including piezoelectric MEMS sensors, actuators, and RF filters. By enabling smaller, higher-performance, and lower-power devices for applications such as Beyond 5G/6G communications, IoT, automotive systems, and medical equipment, we aim to contribute to technological innovation and the advancement of society.

Paper Information and Link:
“Mechanism of the sequential interface structures changes in the epitaxial Pt/ZrO₂/Si”
Azusa N. Hattori, Osamu Nakagawara, Hidekazu Tanaka, Ken Hattori and Kenji Ogata
Japanese Journal of Applied Physics, 65 (2026) 165501.
Mechanism of the sequential interface structures changes in the epitaxial Pt/ZrO₂/Si – IOPscience
https://iopscience.iop.org/article/10.35848/1347-4065/ae86a3