Very low noise silicon planar avalanche photodiodes
A silicon n+–p–π–p+ reach-through avalanche photodiode is described, where the p region has a high-low-high doping profile formed by a combination of ion implantation and epitaxy. Effective noise factors as low as 0.008–0.014 have been realised reproducibly for operation in the near-infrared. The influence of the primary photocurrent in the determination of the excess noise is discussed.