Jan van den Hurk

Direct Observation of Charge Transfer in Solid Electrolyte for Electrochemical Metallization Memory

X-ray absorption spectroscopy study on an electrochemical metallization cell of GeS(x) :Ag shows clear experimental evidence of chemical ionization of the active metal atoms (Ag) and consequent transfer of charge to the electrolyte (GeS(x) ). The valence electron density and its change upon the Ag intercalation are depicted schematically as transparent waves on the Ge-S bond structure in amorphous GeS(x) .

Volatile resistance states in electrochemical metallization cells enabling non-destructive readout of complementary resistive switches

Redox-based resistive memory cells exhibit changes of OFF or intermediate resistance values over time and even ON states can be completely lost in certain cases. The stability of these resistance states and the time until resistance loss strongly depends on the materials system. On the basis of electrical measurements and chemical analysis we found a viable explanation for these volatile resistance states (VRSs) in Ag-GeSx-based electrochemical metallization memory cells and identified a technological application in the field of crossbar memories. Complementary resistive switches usually suffer from the necessity of a destructive read-out procedure increasing wear and reducing read-out speed. From our analysis we deduced a solution to use the VRS as an inherent selector mechanism without the need for additional selector devices.

Ag/GeSx/Pt-based complementary resistive switches for hybrid CMOS/Nanoelectronic logic and memory architectures

Complementary resistive switches based on two anti-serially connected Ag/GeSx/Pt devices were studied. The main focus was placed on the pulse mode properties as typically required in memory and logic applications. A self-designed measurement setup was applied to access each CRS part-cell individually. Our findings reveal the existence of two distinct read voltage regimes enabling both spike read as well as level read approaches. Furthermore, we experimentally verified the theoretically predicted kinetic properties in terms of pulse height vs. switching time relationship. The results obtained by this alternative approach allow a significant improvement of the basic understanding of the interplay between the two part-cells in a complementary resistive switch configuration. Furthermore, from these observations we can deduce a simplified write voltage scheme which is applicable for the considered type of memory cell.