UV-enhanced silicon avalanche photodiodes

Silicon avalanche photodiodes (APDs) fabricated through a deep diffusion process underwent a modified surface treatment in an attempt to improve their response in the ultraviolet region of the optical spectrum. After adjusting the doping profile in the near-surface region of the detectors, APDs were fabricated and tested at several wavelengths from ultraviolet to the near-infrared. At the target wavelength of 355 nm, the detector bandwidth was increased by a factor of 20 over devices fabricated without the modified surface treatment. Modest improvements in the internal quantum efficiency were also measured. Most importantly, the modified detectors maintained the high gain and low noise performance specifications that are hallmarks of traditional deep diffusion APDs.