Excellent Synapse Characteristics of 50 nm Vertical Transistor with WOx channel for High Density Neuromorphic system

We report a WO x based vertical synapse transistor (ST) with excellent device characteristics such as small device area (4F ² ), large conductance range (> 10 ⁵ ), good retention (~ 8 hours) and excellent weight update property. With scaling the device dimension down to 50 nm, significant improvement (>10 ³ ) of switching speed was obtained. To further scale down the device area (2F ² ) and store G ⁺ /G ^- weights, two ST were vertically stacked. We have confirmed that weight update can be maintained without disturbing neighbor cell.