A Novel Approach for Using TSVs As Membrane Capacitance in Neuromorphic 3-D IC

An advanced neurophysiological computing system can incorporate a 3-D integration system composed of emerging nano-scale devices to provide massive parallelism having high speed, low cost, and energy efficient hardware implementation. Due to process technology constraints, a certain amount of redundant through silicon vias (TSVs) and dummy TSVs are always required in a 3-D integrated system. In this paper, we propose to use these redundant and dummy TSVs to supply the neuronal membrane capacitance that maps the membrane electrical activity in a hybrid 3-D neuromorphic system. This proposition could also serve the need of neuronal ion transportation dynamics. We also investigate two new methodologies that could significantly enhance the TSV capacitance in a 3-D neuromorphic system. The capacitance of these enhanced TSVs is studied with analytical models; the accuracy of the models are evaluated against 3-D field extracted values. The advantage of using the TSVs to mimic membrane capacitance in a 3-D neuromorphic chip is demonstrated through comparisons of both silicon area and energy consumption against their 2-D counterpart designs.