Atomic-and Device-Scale Physics of Ion-Transport Memristors
Technical Report,01 Oct 2014,28 Apr 2019
Air Force Research Laboratory Space Vehicles Directorate Kirtland AFB United States
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We report on our key advances in understanding the physics of chalcogenide- and silicon dioxide-based conductive bridge random-access memory CBRAM devices. Specifically, we report on Ag and Sn in Ge2Se3 and in GeSe2, and Ag and Cu in SiO2. We report that Ag and Sn autoionize in Ge2Se3, but not in SiO2. This crucial difference is reflected in the growth of dendrites in both materials. We also found that in Ge2Se3, Ag will readily displace Ge, forming a Ge-Ag dimer. Furthermore, two Ag atoms can form Ag dimers, displacing a pair of Ge atoms, and that this is an exothermic reaction. We have also studied the interaction of oxygen with pure Ge2Se3, and with Ag in the same material. Oxygen molecules will readily dissociate and form a variety of stable and metastable defects. The lowest energy defect is a Ge-O-Ge bridge, thus eliminating Ge-Ge dimers. We also found that oxygen did not readily attack Ge-Ag dimers.
- Atomic and Molecular Physics and Spectroscopy