Project Details

Description

PROGRAMMABLE METALLIZATION CELL PROGRAMABLE METALLIZATION CELL Progammable Metallization Cell Programmable Metallization Cell Programmable Metallization Cell Research Program Programmable Metallization Cell Research Program Under the sponsorship of ., the Programmable Metallization Cell (PMC) research program at ASU has yielded highly significant results. The most notable recent achievements include: 1. Development of models for programming and erase. In this work, performed in conjunction with Politecnico di Milano, we investigated the kinetics involved in the programming operation (i.e., transition from the high resistance to the low resistance state), which occurs by voltage-driven ion migration and electrochemical deposition, and results in conductive filament (CF) formation and growth. The main kinetic parameters controlling the programming operation were extracted from our electrical data. CF growth and corresponding resistance decrease was shown to be controllable with reasonable accuracy in pulse mode by employing a variable load resistance which can dynamically control the programming kinetics. A semi-analytical physical model was developed to account for experimental data and allowed for the engineering of fast and reliable multi-level programming in one transistor - one resistor (1T-1R) devices. The transition from the low-resistance to the high-resistance state was also studied. The stability of the ON state under stress voltage and the erase operation were characterized as a function of the initial resistance in the timescale from 100 s to 100 s. The data suggested that the onoff transition is limited by voltage-driven ion hopping and that filaments with larger size, and hence lower resistance, are more stable. The results were explained with the aid of an analytical model for erase, which is also used to address the tradeoff between ON-state stability and program/erase currents. 2. Fabrication and characterization of Cu-SiO2 based devices. This involved a study of Cu diffusion at various temperatures in thin SiO2 films and the influence of diffusion conditions on the switching of Programmable Metallization Cell devices formed from such Cu-doped films. Film composition and diffusion products were analyzed using secondary ion mass spectroscopy, Rutherford backscattering spectrometry, X-ray diffraction and Raman spectroscopy methods. We found a strong dependence of the diffused Cu concentration, which varied between 0.8 at.% and 103 at. %, on the annealing temperature. X-ray diffraction and Raman studies revealed that Cu does not react with the SiO2 network and remains in elemental form after diffusion for the annealing conditions used. PMC resistive memory cells were fabricated with such Cu-diffused SiO2 films and device performance, including the stability of the switching voltage, was examinedin the context of the material characteristics..
StatusFinished
Effective start/end date3/22/008/31/13

Funding

  • INDUSTRY: Domestic Company: $1,498,136.00

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