Nanofilament Formation and Regeneration During Cu/Al₂O₃ Resistive Memory Switching.
Conductive bridge random access memory (CBRAM) is a leading candidate to supersede flash memory, but poor understanding of its switching process impedes widespread implementation. The underlying physics and basic, unresolved issues such as the connecting filament's growth direction can be revealed with direct imaging, but the nanoscale target region is completely encased and thus difficult to access with real-time, high-resolution probes. In Pt/Al2O3/Cu CBRAM devices with a realistic topology, we find that the filament grows backward toward the source metal electrode. This observation, consistent over many cycles in different devices, corroborates the standard electrochemical metallization model of CBRAM operation. Time-resolved scanning transmission electron microscopy (STEM) reveals distinct nucleation-limited and potential-limited no-growth periods occurring before and after a connection is made, respectively. The subfemtoampere ionic currents visualized move some thousands of atoms during a switch and lag the nanoampere electronic currents.
†Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States.|‡California NanoSystems Institute, University of California, Los Angeles, California 90095, United States.
William A
WA
Hubbard
†Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States.|‡California NanoSystems Institute, University of California, Los Angeles, California 90095, United States.
Alexander
A
Kerelsky
†Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States.|‡California NanoSystems Institute, University of California, Los Angeles, California 90095, United States.
Grant
G
Jasmin
†Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States.|‡California NanoSystems Institute, University of California, Los Angeles, California 90095, United States.
E R
ER
White
†Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States.|‡California NanoSystems Institute, University of California, Los Angeles, California 90095, United States.
Jared
J
Lodico
¶Center for Electron Microscopy and Microanalysis, University of Southern California, Los Angeles, California 90089, United States.
Matthew
M
Mecklenburg
†Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States.|‡California NanoSystems Institute, University of California, Los Angeles, California 90095, United States.
B C
BC
Regan
D000537:Aluminum Oxide / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*
D010984:Platinum; D003300:Copper; D000537:Aluminum Oxide
CBRAM; RRAM; ReRAM; in situ TEM