17 Architectures and Simulations for Nanoprocessor Systems Integrated on the Molecular Scale

This chapter concerns the design, development, and simulation of nanoprocessor systems integrated on the molecular scale. It surveys ongoing research and development on nanoprocessor architectures and discusses challenges in the implementation of such systems. System simulation is used to identify some advantages, issues, and trade-offs in potential implementations. Previously, the authors and their collaborators considered in detail the requirements and likely performance of nanomemory systems. This chapter recapitulates the essential aspects of that earlier work and builds upon those efforts to examine the likely architectures and requirements of nanoprocessors. For nanoprocessor systems, simulation, as well as design and fabrication, embodies unique problems beyond those introduced by the large number of densely-packed, novel nanodevices. For example, unlike the largely homogeneous structure of circuitry in nanomemory arrays, a high degree of variety and inhomogeneity must be present in nanoprocessors. Also, issues of clocking, signal restoration, and power become much more significant. Thus, building and operating nanoprocessor systems will present significant new challenges and require additional innovations in the application of molecular-scale devices and circuits, beyond those already achieved for nanomemories. New nanoelectronic devices, circuits, and architectures will be necessary to perform the more complex and specialized functions inherent in processing systems at the nanometer scale. This chapter highlights the fundamental design requirements of such nanoprocessor systems, presents various device and design options, and discusses their potential implications for system performance.