Monolithic, InGaAs-on-Silicon, Optical Interconnects for Massively Parallel Computing

Period of Performance: 06/28/1996 - 06/28/1998


Phase 2 SBIR

Recipient Firm

Discovery Semiconductors, Inc.
Ewing, NJ 08628
Principal Investigator

Research Topics


A solution to the problem of inter-chip interconnects is proposed that employs electro-optical links implemented monolithically on silicon substrates. This approach addresses the fundamental material incompatability problem of opto-electronics by implementing electronics in silicon and optical components using III-V compounds on a single chip. This is made possible through the use of "selective" epitaxy, a technique that Discovery Seminconductors has developed to grow device grade InGaAs on silicon substrates. Growth of InGaAs crytals on a littice mismatched substrate is improved by limiting the growth area, using GeSi "composite substrates", and controlling the growth conditions. In Phase I, we successfully used this capability to grow dual function InGaAs LED/PINs operating at 1.3 um on a silicon substrate. We also designed the CMOS driver/receiver circuits for the InGaAs diodes. These devices are used to form optical links between separate semiconductor chips. A simple, proximity focussed architecture is presented whre multiple silicon chips are stacked together. The InGaAs LED-Detector pairs monolithically integrated with CMOS circuitry then form the links between the layers of the stack. A 32 bit (2x2) switching device that has all the components required to implement this scheme is proposed for the Phase II work. A more elaborate multi-plane, optically coupled, massively parallel processor will be studied in Phase II.