Plasma-etched polymer waveguides for intrachip optical interconnects

Optical intrachip communication offers the potential advantages of high speed and lack of electrical interference. We report on progress made on an interconnect design using GaAs LEDs, polymer waveguides, and photodiodes in a silicon substrate. The polymer waveguides are fabricated in polyimide or polystyrene materials, and are patterned by reactive ion etching with a tri-level resist system. The photodiodes are of two designs, including one in which the depletion layer lies directly below the waveguide. The LEDs are fabricated from GaAs deposited by MOCVD on a Ge lattice-matching layer placed between the GaAs and the silicon substrate. Test results are presented for the individual components.