Integration of III-V light sources for silicon photonics applications

Abstract: During the last decades, there have been tremendous improvements in Silicon-based transistor technologies such as operational speed increase as well as size and cost reduction. However, the bandwidth in modern processors is significantly limited by the data transfer in the metallic interconnects. Inspired by the long-range telecommunication technologies, the industry is developing the field of integrated optics to transfer data in the pursuit to reach higher bandwidths. A promising approach is using a complementary metal oxide semiconductor (CMOS) compatible with silicon photonics platform. In order to outperform the conventional metallic interconnections, there is a great need for electro-optical components. Up to date, a highly efficient on-chip light source integrated on silicon is missing to complete the full optical link. This thesis aims to design and fabricate a lateral current injection laser integrated on silicon. Optical simulations were conducted to define the parameter space for which a low lasing threshold could be achieved. Prior to the laser fabrication, the passive components of the laser including access waveguides, grating couplers and Bragg reflectors, were separately fabricated and evaluated to ensure their performance. A gain material based on an epitaxially grown multiquantum well stack with an emission peak at 1288nm was successfully integrated on a silicon oxide layer on a silicon substrate. The laser designs were patterned by a wet etch process and the effect of surface preparation prior to the contact regrowth was studied in detail. These results have contributed to a solid establishment of the initial processing steps for the realization of LCI lasers integrated on IBM's silicon chips in the near future.