Enhanced optical detection in MSM photodiodes with nanoscale gratings

Abstract

Summary form only given. Metal-Semiconductor-Metal (MSM) photodetectors are attractive for many optoelectronic applications including the next generation of high performance optical communication interconnects. In particular, Si MSMs are simple to fabricate and compatible with VLSI technology. However, the weak optical absorption of intrinsic Si at GaAs laser wavelengths, due to its indirect bandgap, has resulted in photodetector designs that are unable to deliver acceptable ranges of both efficiency and speed. Although there are high performance GaAs photodetectors currently available, the complex hybrid integration of these into a Si chip negatively affects cost and yield in a production environment. We report on the enhanced optical detection in Si MSM photodetectors with nanoscale grating structures (10-100 nm) fabricated in the active area of the device using interferometric lithography and reactive ion-etching.