Degradation mechanisms in Germanium Electro-Absorption Modulators

Abstract

Reliability analysis on Ge Electro-Absorption Modulators suggest that different physical mechanisms are involved in the dark current degradation during electrical stress. An "incubation time" followed by a power-law dependent dark current increase suggests the filling of pre-existing defects and the creation of traps at the Ge/Si and Ge/Ox interface. Even though the dark current degrades during reliability testing, actual failures are not expected to happen at nominal operation conditions and times. Finally, performance evaluation after more than 4000h of electrical stress, reveals no degradation of the electro-optical parameters.