Interband RTDs with nanoelectronic HBT-LED structures for multiple-valued computation

Abstract

For future nanoelectronic arrays, complex signal processing methods and highly efficient computation are required. A proposed new family of HBT-LED-RTD circuitry chiefly addresses the latter with multiple-valued logic. We use internal optical methods of signal summation in otherwise electronic circuitry. Precision photon streams are generated and summed that are equivalent to electron currents in conventional circuitry. These strictly local interactions of HBTs and LEDs are combined with the folding and thresholding functions of vertically integrated RTDs. Power-of-two bit patterns implement the positive-digit radix-2 MVL. The same circuitry with a summation range of seven also facilitates nanoelectronic signal processing with its innate A/D conversion capability. Our new circuitry is aimed at very high packing density on the order of 10/sup 4/ to 10/sup 6/ gates per IC die. For this purpose it is resistor free and requires no signal-level shifting subcircuits, the HBT-RTD structure is 3-dimensional, and parasitic electrostatic interaction of densely packed circuits is prevented by the optical isolation and the buried optical interconnects. Non-local (especially vertical free-space) optical interconnects are also feasible with our approach using LEDs or microcavity lasers.