Patel, K;
Cottom, J;
Bosman, M;
Kenyon, AJ;
Shluger, AL;
(2019)
An oxygen vacancy mediated Ag reduction and nucleation mechanism in SiO2 RRAM devices.
Microelectronics Reliability
, 98
pp. 144-152.
10.1016/j.microrel.2019.05.005.
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Abstract
Density Functional Theory (DFT) calculations were used to model the incorporation and diffusion of Ag in Ag/SiO 2 /Me (Me = W or Pt) resistive random-access memory (RRAM) devices. We consider an O vacancy (V O ) mediated model of the initial stages of Ag clustering, where the V O is identified as the principle site for Ag + reduction. The Ag + interstitial is calculated to be energetically favoured inside a-SiO 2 at the Fermi energies of Ag, W and Pt. The adiabatic diffusion barriers of Ag + are found to be lower than those for Ag 0 with a strong dependence on the local network structure, supporting Ag + being the mobile species during device operation. Ag + ions bind to V O forming the [Ag/V O ] + complex. The [Ag/V O ] + complex is then reduced by trapping an electron forming [Ag/V O ] 0 . By sampling every V O in a 216-atom cell of a-SiO 2 we demonstrate that this mechanism can occur only at 33%, 33% and 11% of O vacancies at the Ag, W and Pt electrodes, respectively. This complex can subsequently act as a nucleation site for Ag clustering with the formation of [Ag 2 /V O ] + , which is reduced by trapping an extra electron.
| Type: | Article |
|---|---|
| Title: | An oxygen vacancy mediated Ag reduction and nucleation mechanism in SiO2 RRAM devices |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.microrel.2019.05.005 |
| Publisher version: | http://doi.org/10.1016/j.microrel.2019.05.005 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Electronic and Electrical Eng UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10075153 |
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