San Sebastián, Spain — The global semiconductor industry is undergoing a massive transformation, shifting from traditional silicon manufacturing toward highly hybridized optoelectronic architectures. At Graphenea, we are proud to be a driving force in this transition through our active participation in the WOW-2D project (Large-Scale Integration of 2D Optoelectronic Devices in Standard Photonic PIC Platforms), which just finished.

Funded and supported by CDTI within its “Líneas Estratégicas 2022” program, WOW-2D united Graphenea with leading academic fabrication experts at the University of Granada (UGR), characterization experts at the Polytechnical University of Madrid (UPM) and the integrated photonics team at the Institute of Microelectronics of Barcelona (IMB-CNM, CSIC). Together, the consortium established a manufacturing workflow needed to propel hybrid 2D-photonic systems from the lab to ubiquitous commercial realities.

Overcoming Integration Bottlenecks

Historically, integrating 2D materials like single layer graphene (SLG) into Photonic Integrated Circuits (PICs) has been hindered by complex transfer processes that introduce defects and metallic contamination. To meet the rigorous demands of CMOS circuitry, Graphenea adapted its transfer process to make it compatible with the materials and temperatures required for BEOL integration. This, in combination with low-T deposition of Transition Metal Dichalcogenides (TMDs) by UGR, ensures a seamless combination with CMOS wafers.

By enabling advanced electrochemical delamination and direct dry-transfer methods, we are clearing the path for mass integration on wafers up to 200 mm, ensuring seamless van der Waals contact with the underlying photonic structures.

Furthermore the consortium was able to create bilayer structures for modulation, and hybrid SLG/TMD/SLG for emission and photodetection.

Visible-Spectrum Photonics and Wafer-on-Wafer (WoW) Bonding

While Graphenea provides the active 2D overlay, our partners at IMB-CNM are engineering the passive optical routing. Moving beyond standard silicon, the project utilizes silicon nitride (Si3N4) waveguides optimized for the visible spectrum.

The true breakthrough of the WOW-2D project, however, lies in its namesake: Wafer-on-Wafer (WoW) heterogeneous integration. All the tools and processes used and developed within the project framework are wafer-scale compatible, meaning that process scalability from a small prototype to a mass manufacturable device is nearly immediate given the wafer scale focus of the project.

The implications of this platform are vast. By merging visible-light evanescent fields with graphene’s supreme electrical sensitivity, the WOW-2D architecture enables the creation of optoelectronic sensors and electrooptical light sources, modulators and photodetectors.

To democratize access to these breakthroughs, Graphenea is continuously integrating these capabilities into our Graphene Foundry (GFAB) services. Through our regular Multi-Project Wafer (MPW) runs and strategic partnerships we are empowering developers worldwide to prototype next-generation flexible electronics, advanced diagnostic tools, and neuromorphic computing architectures.

Through the WOW-2D initiative, Graphenea and its partners are not only defining the future of semiconductor engineering but also securing Europe’s technological sovereignty in the next era of high-performance computing and sensing.