Development Of Silicon-based Electro-optic Modulator

This work relies on the 8-inch semiconductor experimental line of“the Intergrated Circuit Advanced Process R&D center of Institute of Microelectronics of Chinese Academy of Sciences”and investigates the manufacturing technology of silicon-based electro-optic modulators.The manufacturing process modules of the electro-optic modulator is studied both by simulation and experiment.A Mach-Zehnder electro-optic modulator is fabricated ultimately.A PN junction is formed by doping on the ridge of the waveguide and activation.Therefore,the refractive index of the waveguide could be controlled by controlling the free carrier concentration and profiles of the PN junction.We have developed some key manufacturing process modules for the fabrication of silicon-based electro-optic modulators.This paper described the fabrication processes of electro-optic modulators and explained the key process steps in detail.The target concentration of active dopants for the n-type and p-type region are 2e17 cm^-3 and 4e17 cm^-3,respectively,by simulation.According to the test results of electro-optic modulator,the modulation bandwidth exceeds 22.5 GHz and the max modulation rate exceed 30 Gbps.After the manufacture of the electro-optic modulator,some slight damages on the ridged waveguides are found by SEM and we re-design some single experiments for finding the reasons for causing the problem and propose some corresponding solutions.The problems is solved by reducing the use of antireflective coatings in ion implantation modules and optimizing the anti-reflective coating etch process finally.