Silicon-On-Sapphire for Opto-electronic VLSI

Internal data rates of processors fabricated in deep submicron CMOS technology have exceeded gigahertz rates. While processing proceeds at gigahertz internally, off chip wires have held inter-chip clock rates in the hundreds of megahertz. The rate of inter-chip communication is now the bottleneck in high performance systems.

Optical inter and intra-chip communication has the potential to solve interconnect problems. Inter-chip opto-electronic communication is complicated by the difficulty of routing optical signals in parallel around substrates. Furthermore, parasitic effects in today's bulk CMOS processes limit the design of CMOS compatible high performance electronics for optical channel interfaces.

In this seminar, I focus on interconnect designs based upon the newly developed ultra-thin silicon-on-sapphire CMOS technology. By exploiting the characteristics of this technology I will show how one can construct opto-electronic modules that allow for efficient communication at chip-to-chip distances. Interconnects constructed in this way avoid conventional CMOS routing and speed limitations. I will also consider various receiver architectures for power efficient short distance bit transfer in the context of an optical link. I will conclude with a discussion of possible architectures and applications of optically connected CMOS systems made possible by this new technology.