NOR-Type Flash Array Based on Four-Terminal TFT Synaptic Devices Capable of Selective Program/Erase Exploiting Fowler-Nordheim Tunneling

A NOR-type flash array is proposed as a synaptic device array for on-chip training neuromorphic systems. Compared to the previously proposed AND-type array, the orthogonal drain-line (DL) and source-line (SL) enable array transpose for backpropagation. The proposed array enables low-power selective program/erase operation using additional p-body-line (PL) and shows relatively linear long-term potentiation/depression (LTP/LTD) characteristics due to the device structure. Additionally, the NOR-type array exhibits accurate current sum capability.