Theoretical study on sensing performance of hydrogen annealed silicon waveguides

Due to the surface diffusion movement of Si atom in hydrogen annealing process, the sharply formed corners of waveguides will be rounded and its sidewall profile could be reformed. In this paper, the performances of microring sensors based on three different gradual annealed structures, strip with large/small round corners and cylinder waveguide, are investigated theoretically. Characteristic parameters of sensors based on cylinder waveguide, sensitivity, Q factor, and measuring range are analyzed and compared with that of sensors based on the widely-used strip and slot waveguides. Simulation results demonstrate that the sensitivity of microring is significantly increased after annealing with comparable Q factor and measuring range. The hydrogen annealing process promises a feasible and effective method to improve the performance of biosensors in the future.