SiGeSn Laser for Silicon Photonics

• Applicants: Dan Buca, Ph.D.; Professor Giovanni Capellini, Ph.D.; Dr.-Ing. Michael Oehme; Professor Jeremy Witzens, Ph.D.
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering
• Term: from 2016 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 299480227

An electrically pumped group IV laser grown on silicon remains one of the outstanding objectives of silicon photonics. The ternary material system SiGeSn remains the leading contender for its realization.During the first funding period, the applicant team has defined the state of the art of SiGeSn lasers in several key aspects: The first GeSn laser optically pumped at cryogenic temperatures was demonstrated by the group of Dr. Dan Buca in 2015, shortly before the beginning of the first phase of the project. Since then, the applicant team has demonstrated the first GeSn microdisk lasers and the first SiGeSn multi-quantum-well lasers. The demonstrated lasing threshold of 35 kW/cm2 also remains, to the best of our knowledge, the lowest threshold reported for SiGeSn lasers so far. A modeling methodology has been established in the commercial semiconductor modeling tool TCAD from Synopsys and software modules adapted in cooperation with the company. The first SiGeSn electro-optical devices (LED) was demonstrated during the first phase of the project.In the requested second funding period, we will focus on improving the lasers in view of realizing an electrically pumped, room temperature laser. To reach this objective, tensile straining by means of silicon nitride cladding layers will be added to the tool kit in order to improve the properties of the gain material. For a good electrical contact with small series resistances highly doped contact layers will be grown epitaxially. Moreover, almost fully undercut microdisk lasers will be modified to larger cavity ring lasers with partial undercut, to improve heat sinking and increase output power levels.The roles of the four involved research institutions are clearly defined, with the RWTH Aachen responsible for modeling efforts, the Forschungszentrum Jülich for epitaxial growth, the University of Stuttgart for device fabrication and the Leibniz Institute IHP for material and device characterization.

• DFG Programme: Research Grants
• International Connection: United Kingdom
• Cooperation Partner: Professor Dr. Zoran Ikonic