Effect of Ag source layer thickness on the switching mechanism of TiN/Ag/SiN_x/TiN conductive bridging random access memory observed at sub-µA current

Experiments are conducted to compare the resistive switching characteristics for several samples with different amounts of Ag deposition in TiN/Ag/SiN_x/TiN conductive bridging random access memory (CBRAM). The compliance current in TiN/Ag/SiN_x/TiN CBRAM determines the volatile/non-volatile memory operation as the current level controls the strength of the filament made of Ag. The transient measurement showed that the effective thickness of Ag source layer in the TiN/Ag/SiN_x/TiN controls the supply of the Ag atoms into the insulating layer, affecting the strength of the conductive bridge. The mechanism for the switching characteristics and the volatility trend with the amount of Ag deposition is closely investigated using transmission electron microscopy and scanning electron microscopy images. The device shows the conductance potentiation by a voltage pulse train under 1 µA current level, and the higher potentiation rate is observed in the CBRAM with thick Ag source layer. (paper)