Development of a monolithic very large scale optoelectronic integrated circuit technology

Abstract

Optical interconnects have been proposed for use in high-speed digital systems as a means of overcoming the performance limitations of electrical interconnects at length scales ranging from one millimeter to one hundred meters. To achieve this goal, an optoelectronic very large scale integration (OE-VLSI) technology is needed which closely couples large numbers of optoelectronic devices, such as light emitters and photodetectors, with complex electronics. This thesis has been concerned with the development of an optoelectronic integration technology known as Epitaxy-on-Electronics (EoE). EoE produces monolithic optoelectronic integrated circuits (OEICs) by combining conventional epitaxial growth and fabrication techniques with commercial GaAs VLSI electronics. Proceeding from previous feasibility demonstrations, the growth and fabrication practices underlying the EoE integration process have been extensively revised and extended. The effectiveness of the resulting process has been demonstrated by fabricating the first monolithic, VLSI-complexity OEICs featuring light-emitting diodes (LEDs). As part of a research foundry project, components of this type were designed and tested by a number of groups involved in optical interconnect system development. To further realize the potential of the EoE technology, and to make its capabilities accessible to a broader user community, the focus of this work was extended beyond the development of the integration process to encompass a study of high-speed photodetectors implemented in the GaAs VLSI process, to examine the role of the EoE technology within optical interconnect applications, to formulate an analytical framework for the design of digital optical interconnects, and to implement compact, low power laser driver and optical receiver circuitry needed to implement these interconnects.