Avalanche photodiodes with lower excess noise and lower bandwidth variation

Abstract

An avalanche photodiode includes a silicon layer on a substrate; a germanium layer on the silicon layer; and a plurality of contacts including a cathode, an anode, and at least two separate gain tuning contacts configured to adjust an electric field to tune multiplication of carriers. The at least two separate gain tuning contacts are configured to control the electric field in the germanium layer and silicon layer. The at least two separate gain tuning contacts are configured to tailor the electric field such that the multiplication of carriers is greater in the silicon layer than the germanium layer. This added gain tuning control can be used to tailor the electric field profile such that multiplication happens mostly in silicon to achieve lower excess noise and little to no bandwidth variation.

Dependencies are inferred from the claim text.