Core-Shell Dual-Gate Nanowire Memory as a Synaptic Device for Neuromorphic Application

Abstract

In this work, a synaptic device for neuromorphic system is proposed and designed to emulate the biological behaviors in the novel device structure of core-shell dual-gate (CSDG) nanowire flash memory. Floating-body effect in the device and charge trapping/de-trapping in the nitride layer are found to be effective for short-term potentiation (STP), long-term potentiation (LTP), and long-term depression (LTD), respectively. STP realizes a temporary potentiation in the artificial neural network, and it can transit to LTP through the process of rehearsal and meaningful association. The transition takes place at the 10th pulse in a permissibly optimized CSDG synaptic device. The proposed device shows a stronger capacitive coupling between the dual gates, which forms a deeper potential well for charge storing and achieves better memory performance metrics such as sensing margin and retention time. The series of results reveal that the synaptic memory device is applicable to neuromorphic system due to the stronger gate controllability, multi-level weight adjustability, and Si processing compatibility.

Keywords

• Synaptic device
• neuromorphic system
• core-shell dual-gate
• nanowire
• flash memory
• short-term potentiation (STP)