设计了一种Ge/Si波导集成型雪崩光电二极管(APD)。器件采用将Si波导层置于Ge吸收层之下的结构, 光经波导层进入吸收层只需一次耦合, 降低了光的损耗, 提高了光的吸收率和光电流。采用silvaco软件对器件的结构和性能进行仿真, 结果表明: 器件的雪崩击穿电压为-28V, 最大内量子效率达到89%, 在1.15~1.60μm范围内具有较高响应度, 峰值波长位于1.31μm, 单位响应度最高达0.74A/W, 3dB带宽为10GHz。

In this paper, A Ge/Si Waveguide-Integrated avalanche photodetector (APD) is proposed. The Si waveguide layer is designed to be located below the Ge absorption layer, so only one coupling is needed when the light is coupled into the absorption layer from the waveguide layer, which results in the reduction of the light coupling loss, and the increase of the light absorption rate and photocurrent. The structure and performance of APD is simulated with silvaco software, the simulation results show that the avalanche breakdown voltage is -28V, the maximum internal quantum efficiency is 89%, the higher degree of the responsibility is obtained in the range of 1.15~1.60μm, the wavelength of peak responsibility is 1.31μm, the highest responsibility is 0.74A/W, and 3dB bandwidth is 10GHz.