Vertical 3-Terminal Artificial Synaptic Devices

Abstract

Recently, synaptic devices have the advantages of being able to process information in parallel. However, nondestructive weight control is limited in 2-terminal synaptic devices because reading and writing are conducted in a common electrode. Hence, 3-terminal synaptic devices with separately reading and writing processes are currently emerging for not only nondestructive weight control without data loss but also a very short vertical channel length. Since the length of the vertical channel is determined as the thickness of the active layer, nanometer range channel length can be achieved. According to the nano-scaled channel length, vertical 3-terminal artificial device can be operated with low voltage and energy consumption. In this review paper, vertical 3-terminal artificial synaptic devices were classified by electric field transmission or ion migration into organic semiconductor. According to a recent study, vertical 3-terminal artificial synapse was able to simulate a biological synapse even with a low driving voltage of up to 10 μV and a current density of MAcm−2 level. This review article gives an overview of vertical 3-terminal artificial synaptic devices, and suggest a practical strategy to achieve the massive data processing with high speed and low power consumption.