Proceedings Article | 5 November 2018
KEYWORDS: Waveguides, Silicon photonics, Modulators, Photodetectors, Wave propagation, Optical components
Silicon photonics is poised to revolutionize many application areas, such as telecommunication, date centers, biosensing, high performance computing, etc. A whole silicon photonics process flow based on 200mm CMOS platform and the performance of photonics devices were described in this paper. A series of optimized process, including photolithography, etching, hydrogen annealing, ion implantation, epitaxial growth, etc., are implemented to fabricate low-loss passive devices and high-speed active devices. The propagation loss is sensitive to sidewall roughness originated from the waveguide-patterning process. Hydrogen annealing is an effective method to reduce the propagation loss of waveguides. Every level of implantation in top silicon layer is performed respectively, including the p++, p+, p, n++, n+ and n doping for the modulators, p++, p+, n++ and n+ implants for Ge photodetector. Epitaxial Ge is considered to be an excellent material for photodetectors. High-quality Ge on silicon is grown via selective epitaxy using SiO2 as growth mask, followed by a CMP process to planarize the top of the selectively grown Ge. In our platform, the propagation loss of waveguide is measured to be 2.5dB/cm, the insertion loss of grating coupler at 1550nm is 4.5dB/facet, the crosstalk of cross waveguide is lower than -30dB, the insertion loss of 8 channels 200GHz AWG is approximately 3.3dB, the 3dB bandwidth of MZ modulator achieves higher than 20GHz, and the Ge photodetector operates at high data rate exceeding 40Gbps.
