Reverse current reduction of Ge pin photodiodes on Si without post-growth annealing

摘要

A new approach to reduce the reverse current of Ge pin photodiodes on Si is presented, in which an i-Si layer is inserted between Ge and top Si layers to reduce the electric field in the Ge layer. Without post-growth annealing, the reverse current density is reduced to ～10 mA/cm{sup}2 at -1 V, i.e. one order of magnitude lower than that of the reference photodiode without i-Si layer. The responsivity of the Ge photodiode reaches the nearly theoretical maximum. This "non-thermal" approach to reduce reverse current should accelerate electronics-photonics convergence using Ge on the Si CMOS platform.