Researchers developed a way to implement optical devices made of different materials onto a single chip.
Silicon-based chips have enabled increasingly more powerful and flexible systems on a chip. Whereas optical systems on chips require integration of various distinct materials on a single chip, and therefore, the development is not yet seen.
Dimitars Jevtics from the University of Strathclyde in the UK and his colleagues developed a new transfer printing process and demonstrated its ability to place devices made of multiple materials on a single chip.
“On-chip optical communications, for example, will require the assembly of optical sources, channels and detectors onto sub-assemblies that can be integrated with silicon chips,” said Jevtics. “Our transfer printing process could be scaled up to integrate thousands of devices made from different materials onto a single wafer. This would enable micron-scale optical devices to be incorporated into future computer chips for high-density communications or into lab-on-a-chip bio-sensing platforms.”
One of the major challenges in implementing multiple materials on a chip is trying to place them very close together without disturbing devices that are already on the chip. To avoid this issue, researchers developed a method based on reversible adhesion in which a device is picked up and released from its growth substrate and placed onto a new surface.
The substrate on which it is going to be placed is positioned under the suspended device and accurately aligned using a microscope. After alignment, the surfaces are brought close to each other, releasing the polymer stamp and depositing it onto the target surface.
“By carefully designing the geometry of the stamp to match the device and controlling the stickiness of the polymer material, we can engineer whether a device will be picked up or released,” said Jevtics. “When optimized, this process does not induce any damage and can be scaled up using automation to be compatible with wafer-scale manufacturing.”
“As a manufacturing technique, this printing approach is not limited to optical devices,” said Jevtics. “We hope that electronics specialists will also see possibilities for how it could be applied in future systems.”
The research has been published in the journal Optical Materials Express.