Modeling of the performance of carbon nanotube bundle, cu/low-k and optical on-chip global interconnects

Abstract

In this work, we have quantified and compared the performance of carbon nanotube (CNT) and optical interconnects with the existing technology of Cu/low-K interconnects for future high-performance ICs. We present these comparisons not only in terms of commonly used metrics such as latency and power dissipation, but also compare them using important compound performance metrics, such as, bandwidth density per latency per power. We find that the optical interconnect has the lowest latency for global interconnects and the highest achievable bandwidth density using wavelength division multiplexing. However, the value of the compound metric is the highest for either CNTs or optical technology depending on the required bandwidth density. Both these technologies significantly outperform the existing Cu/low-K interconnect technology. We have also extensively examined the impact of device, material, and system parameters of the novel interconnect technologies on the comparisons. We find that using small detector and modulator capacitances optical interconnects (~10fF) yield superior performance compared to CNTs (electron mean free path of 0.9mm) and Cu for switching activities greater than 35% and 20%, respectively. However, improving mean free path of CNTs to ~2.8μm increases the crossover switching activity to 80%.