[1] Improved performance of computer systems has been achieved, in large part, by downscaling the IC minimum feature size.
This allows the basic IC building block, the transistor, to operate at a higher frequency, performing more computations per second.
However, downscaling of the minimum feature size also results in tighter packing of the wires on a microprocessor, which increases parasitic capacitance and signal propagation delay.
This phenomenon, known as an "interconnect bottleneck", is becoming a major problem in high-performance computer systems.
There are still many materials, fabrication, and packaging challenges in integrating optic and electronic technologies.