A Vertical Silicon Nanowire Based Single Transistor Neuron with Excitatory, Inhibitory, and Myelination Functions for Highly Scalable Neuromorphic Hardware
Joon‐Kyu Han, Jungyeop Oh, Ji‐Man Yu, Sung‐Yool Choi, Yang‐Kyu Choi
Abstract
Abstract A single transistor neuron (1T‐neuron) is demonstrated by using a vertically protruded nanowire from an 8 in. silicon (Si) wafer. The 1T‐neuron adopts a gate‐all‐around structure to completely surround the Si nanowire (Si‐NW) to make a floating body and allow aggressive downscaling. The Si‐NW is composed of an n + drain at the top, n + source at the bottom, and p‐type floating body at the middle, which are self‐aligned vertically. Thus, it occupies a small footprint area. The gate controls an excitatory/inhibitory function. In addition, myelination of a biological neuron that changes membrane capacitance is mimicked by an inherently asymmetric source/drain structure. Two spiking frequencies at the same input current are controlled by whether the neuron is myelinated or unmyelinated. Using the vertical 1T‐neuron, pattern recognition is demonstrated with both measurements and semiempirical circuit simulations. Furthermore, handwritten numbers in the MNIST database are recognized with accuracy of 93% by software‐based simulations. Applicability of the vertical 1T‐neuron to various neural networks is verified, including a single‐layer perceptron, multilayer perceptron, and spiking neural network.