Photonic Crystal Microcavities in a Microelectronics 45-nm SOI CMOS Technology

We demonstrate the first monolithically integrated linear photonic crystal microcavities in an advanced silicon-on-insulator complementary metal–oxide–semiconductor microelectronics process (IBM 45nm 12SOI) with no in-foundry process modifications and a single postprocessing step. The cavities were integrated into a standard microelectronics design flow meeting process design rules, and fabricated alongside transistors native to the process. We demonstrate both 1520- and 1180-nm wavelength cavity designs using different cavity implementations due to design rule constraints. For the 1520- and 1180-nm designs, loaded quality factors of 2000 and 4000 are measured, and intrinsic quality factors of 100 000 and 60 000 are extracted. We also demonstrate an evanescent coupling geometry that decouples the cavity and waveguide-coupling design.