Research on the Structure Design of Silicon Avalanche Photodiode with Near-Ultraviolet High Responsivity

To improve the low responsivity of the silicon avalanche photodiode in the near-ultraviolet wavelength range, we designed a near-ultraviolet highly responsive Si-APD basic structure with a multiplication layer neighboring the photosensitive surface through the analysis of the optical absorption characteristics, junction breakdown characteristics, and avalanche multiplication characteristics. The dark current and electric field distribution of the device were investigated. Meanwhile, the structural parameters of the surface non-depleted layer, multiplication layer, and absorption layer were optimized. It was found that the breakdown voltage of the device is 21.07 V. At an applied bias voltage of 20.02 V, the device exhibits a responsivity of 6.79–14.51 A/W in the wavelength range of 300–400 nm. These results provide valuable insights for the design of silicon avalanche photodiode with high responsivity in the near-ultraviolet range.