Reactive Ion Beam Etching of PIC Materials with High Optical Performance

Driven by the rapid growth of AI applications, photonics is becoming increasingly important, creating a demand for advanced materials and fabrication technologies. Lithium niobate (LN) has emerged as a promising platform for photonic integrated circuits and is expected to play a key role in future applications.

However, current structuring techniques using plasma-based etching tools face significant challenges in achieving high-quality waveguides. In contrast, ion beam etching enables the fabrication of high-quality devices with low optical losses, owing to reduced sidewall roughness and significantly diminished fencing effects. Furthermore, ion beam etching offers additional design flexibility, such as the realization of variable sidewall angles.

This work discusses the typical challenges associated with ion beam etching and presents results obtained using reactive ion beam etching (RIBE). Well selected gas mixtures and substrate tilt angles are identified and a sidewall cleaning process is introduced to further suppress fencing and improve the etch quality.

About the presenter
Susanne Hartmann earned her master’s degree in physics from Chemnitz University of Technology in 2015, completing her thesis within the semiconductor physics research group. She subsequently worked, with a focus on electron beam lithography, first as a physicist at Anfatec Instruments AG, and later as a research associate at the Center for Micro- and Nanotechnologies of Chemnitz University of Technology. In 2025, she joined the R&D department of scia Systems.