# Crystal Substrate Bonding Technologies and Algorithms (CRYSTAL)

Canonical: https://abierto.us/opportunities/darpaea250204

- Solicitation number: DARPA-EA-25-02-04
- Notice type: Solicitation
- Status: Closed. Deadline was June 16, 2025
- Department: Department of Defense
- Agency: Defense Advanced Research Projects Agency
- Contracting office: Def Advanced Research Projects Agcy (HR0011)
- NAICS: 541715 Research and Development in the Physical, Engineering, and Life Sciences (except Nanotechnology and Biotechnology)
- Product or service code: AC11 National Defense R&D Services; Department Of Defense - Military; Basic Research
- First posted: February 14, 2025
- Last posted: February 14, 2025
- SAM.gov: https://sam.gov/workspace/contract/opp/d07df126129d4f98bd0a8d38aedf4218/view

## Description

Bonded single crystal thin film multi-functional materials (electro-optic, acousto-electric, acousto-optic, magneto-optic or multi-ferroic materials) are vital for diverse sensing and communications technologies (integrated quantum, photonic, terahertz [THz], radio frequency [RF], and actuator platforms). Wafer bonding onto compatible substrates is the critical step for integrating single crystal thin films into multi-functional devices and systems.

There is currently no method to analytically investigate wafer bonding processes. Brute force experimentation is required for initial process development, and subsequent changes in materials or device parameters necessitate significant additional trial and error, incurring huge costs, prolonging timeframes, thus limiting exploration of novel material systems.

Because there are no generalizable approaches to model wafer bonding between thin film crystals and substrates, wafer bonding process development remains highly empirical. As a result, the wafer bonding process is highly specific to select materials and device parameters and is limited by experimental knowledge to a small subset of known materials and device parameters.

As an example, although lithium niobate on insulator (LNOI) exhibits promising piezo-electric and electro-optic properties, the lack of predictive wafer bonding models impedes development of novel applications and limits scalable integration. The ability to predictively model wafer bonding of thin film crystals would rapidly accelerate the research and development of multi-functional materials, and their fabrication and scalable integration in diverse applications.

This ARC Opportunity is soliciting ideas to explore the following question: To accelerate development and integration of multi-functional materials, how do we create generalizable models to explore thin film crystal bonding onto suitable substrates under diverse real-world process conditions and parameters?

## Publications

- February 14, 2025: Solicitation, due June 16, 2025. Notice d07df126129d4f98bd0a8d38aedf4218. https://sam.gov/workspace/contract/opp/d07df126129d4f98bd0a8d38aedf4218/view

## Points of contact

- BAA Coordinator, CRYSTAL@darpa.mil

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