Improving contact design for micro-disc based lasers in integrated circuits

Using III-V bonding on silicon wafers, thin microdisk based lasers are well adapted to introduce optical functionalities in integrated circuits. For mass production and implementation easiness, electrically driven sources are required, and consequently metal based elements and absorbing medium are necessary. In order to lower absorption losses, we propose to optimize the geometry of contacts. After a 3D finite difference time domain (FDTD) confrontation, we demonstrate that our very fast calculation model can be used to design top contacts. We also expose some improvements in order to reduce useless current lines in the micro-disk without increasing the fabrication cost. At last, we discuss the influence of the electrical PIN structure.