Electrodeposit Formation in Solid Electrolytes

Devices based on polarity-dependent switching in solid electrolytes show great promise as next generation memory and perhaps even logic devices. These elements operate by the formation of robust but reversible electrodeposited conducting pathways which can be grown and dissolved at low voltage and current. Although such devices have been well characterized, little has been presented on the exact growth mechanism and nature of the conducting links themselves. In this paper we will show and discuss examples of electrodeposition within ternary silver-chalcogenide electrolyte device structures. The electrolyte was sectioned using focused ion beam milling and imaged with an in-situ scanning electron microscope to reveal the profile of the structure. A variety of Ag electrodeposits were imaged in overwritten devices and it was clear that programming times in the order of a few seconds will create multiple deposits on the inert cathode, some of which appear to extend through to the anode. The electron beam itself was also used to reduce silver ions within the electrolyte to reveal how the electrodeposits might nucleate on the Ag-rich phases within the film.