PROJECT TITLE :

Programming Current Reduction via Enhanced Asymmetry-Induced Thermoelectric Effects in Vertical Nanopillar Phase-Change Memory Cells

ABSTRACT:

Thermoelectric effects are envisioned to cut back programming currents in nanopillar section-amendment memory (PCM) cells. However, thanks to the inherent symmetry in such a structure, the contribution thanks to thermoelectric effects on programming currents is minimal. In this paper, we have a tendency to propose a hybrid PCM structure, that incorporates a twofold asymmetry specifically aimed to favorably enhance the thermoelectric effects. The first asymmetry is introduced via an interface layer of low thermal conductivity and high negative Seebeck coefficient, such as polycrystalline SiGe, between the underside electrode contact and also the active region comprising the section-modification material. This results in an enhanced Peltier heating of the active material. The second one is introduced structurally via a taper that ends up in an angle-dependent Thomson heating inside the active region. Numerous device geometries are analyzed using a pair of-D-axis-symmetric simulations to predict the impact on programming currents furthermore for different thicknesses of the interface layer. A programming current reduction of up to sixty% is predicted for specific cell geometries. Remarkably, we have a tendency to notice that thanks to an interplay of Thomson cooling in the electrode and therefore the uneven heating profile within the active region, the predicted programming current reduction is resilient to fabrication variability.