Reconfigurable Field-Effect Transistor as a Synaptic Device for XNOR Binary Neural Network

A reconfigurable field-effect transistor (RFET) with memory functionality is proposed as a new high-density synaptic device capable of exclusive NOR (XNOR) operation for a binary neural network (BNN). A RFET with three gates is used in this letter, consisting of two program gates (PGs) electrically connected to each other and a control gate (CG) between the PGs. By changing the polarity of the PG bias or the polarity of the charge trapped in Si 3 N 4 layer on the PGs, the RFET operates as an <tex-math notation="LaTeX">n </tex-math> - or a <tex-math notation="LaTeX">p </tex-math> -MOSFET having a CG as a switching gate. The XNOR operation is successfully demonstrated in a fabricated RFET. The on/off current ratio (the ratio of 1 to 0 in the result of the XNOR operation) is ~10 4 and the current is ~1 nA/ <tex-math notation="LaTeX">μ m </tex-math> . Using a RFET as a synaptic device for a BNN is efficient in terms of the area (~8F 2 /synapse) because XNOR operation can be performed using only one RFET.