Fully embedded photonic crystal cavity with Q=0.6 million fabricated within a full-process CMOS multiproject wafer

A two dimensional photonic crystal (PhC) resonator, based on a recent design concept, entirely embedded in Silica, is fabricated in a CMOS full-process multiproject wafer, including additional steps such as implantation, metalization, Germanium deposition and planarization. A large loaded Q-factor (5.9 × 10⁵) is achieved without removal of the silica cladding. A statistical analysis over 56 devices leads to an average value for the loaded Q of 4 × 10⁵, in close agreement with calculations. An upper boundary for the fabrication disorder is estimated to 1.2 nm.