Integration of Silicon Germanium to a Silicon Photonics Platform

The variety of SiGe compositions commonly target specific applications and most of the methods used to grow compound material only allow to achieve a single composition on a specific layer within an epitaxy process step. A novel epitaxy method based on liquid phase epitaxy (LPE) or rapid melt growth (RMG) gives the unique possibility of more than one SiGe composition across the wafer and makes possible to have more than one type of SiGe based device using just one deposition and one anneal step.
The aim of this PhD project is to use the RMG epitaxy method to fabricate waveguide integrated devices such as detector or modulator. It is expected that the RMG process will reduce the defect density and give enough good quality material for the integration. The process development and integration of the RMG method of SiGe on SOI and the fabrication of SiGe waveguides is therefore the target of the currently conducted work.

Silicon photonics is currently an expanding platform for the integration of optics and electronic circuits. In a time of increasing demand for faster and more efficient interconnects, the substantial amount of research data available for silicon in electronics facilitates the migration of interconnect technology towards CMOS compatible photonic devices and systems
Silicon germanium is a promising material for such high performance telecommunication devices. Thanks to its physical properties and fabrication methods previously demonstrated using rapid melt growth (RMG) enabling crystal composition engineering, it is possible to design cutting-edge devices with this material.
The fabrication process for the integration of the SiGe RMG to SOI to form Si to Ge and SiGe waveguides transition is in progress. Masks have been designed in order to provide enable the waveguide integration process following earlier process development tests. The new integration process being developed is an efficient and fast way to achieve this aim. This report is a review of the project progress throughout the last 8 months of my work as a PhD student at the University of Southampton within Silicon Photonics group.