Experimental study of plane electrode thickness scaling for 3D vertical resistive random access memory

The vertical scaling for the multi-layer stacked 3D vertical resistive random access memory (RRAM) cross-point array is investigated. The thickness of the multi-layer stack for a 3D RRAM is a key factor for determining the storage density. A vertical RRAM cell with plane electrode thickness (tm) scaled down to 5 nm, aiming to minimize 3D stack height, is experimentally demonstrated. An improvement factor of 5 in device density can be achieved as compared to a previous demonstration using a 22 nm thick plane electrode. It is projected that 37 layers can be stacked for a lithographic half-pitch (F) = 26 nm and total thickness of one stack (T) = 21 nm, delivering a bit density of 72.8 nm(2)/cell.