Photonic Embedding of Active Region Laser Chips on Silicon
Silicon is the key component in the manufacture of integrated circuits. It is inexpensive, mechanically stable and its processing has been well researched. However, it is not optically active and therefore unsuitable for optical circuits. The integration of optically active III-V semiconductors in silicon provides a cost-effective way to produce electro-optical integrated circuits. These are widely used in inter- and intra-datacenter transmission where high bandwidths are required with low space requirements and high energy efficiency.
The BMBF project PEARLS deals with the production of such circuits (so-called EPICs), which require little packaging technology due to the elimination of external lasers and are very compact. III V semiconductor lasers are to be integrated into a silicon photonics platform for the first time using thin-film transfer print processes.
The subproject at the Kassel University deals with the growth of the III V materials as well as the production of the membranes and laser structures to be transferred.
The laser material is produced by molecular beam epitaxy due to the excellent material quality. Based on indium phosphide, not only quantum dot material with a wavelength of 1.55 µm for transmission over long distances, but for the first time also material with a wavelength of 1.3 µm for short-range transmission will be produced.
The laser material is to be transferred in the form of small membranes by transfer printing onto silicon wafers with a diameter of 200 mm. The production of these membrane structures is another aspect of the subproject at the Kassel University. A special focus here is on the design of the support structures, which hold the membranes in place until transfer and tear off during transfer.
After the membranes have been transferred to silicon at the IHP in Frankfurt/Oder, the laser structures are etched in Kassel. Working on a diameter of 200 mm is a considerable challenge. However, the laser production after the transfer is expected to result in greater accuracy in the alignment of the laser to the silicon platform.
The contacting and completion of the EPIC will take place at the Fraunhofer Institute IZM in Berlin and at the IHP.
List of partners:
IHP (Leibniz-Institut für innovative Mikroelektronik)
Fraunhofer-Institut für Zuverlässigkeit und Mikrointegration
Technion – Israel Institute of Technology
ADVA Optical Networking SE