SPICE simulation of nanoscale non-crystalline silicon TFTs in spiking neuron circuits

Electrical characteristics of nano-crystalline silicon (nc-Si) thin-film transistors (TFTs) are fit using SPICE device models. The corresponding device model geometry is then extrapolated down to submicron dimensions using electrical data measured on a-Si:H transistors as justification. The nanoscale devices are then used to simulate a spiking neuron circuit. The frequency of output voltage pulses in the circuit is a function of the input current. Various loads are added to the output to represent driving of many synapses. Frequency versus current curves from the circuit simulations are compared to biological models. The similarities demonstrate the feasibility of using low-temperature, large-area semiconductor materials such as nc-Si in nanoscale devices to implement neuromorphic electronic designs.