Impact of thermoelectric phenomena on phase-change memory performance metrics and scaling

Abstract

The coupled transport of heat and electrical current, or thermoelectric phenomena, can strongly influence the temperature distribution and figures of merit for phase-change memory (PCM). This paper simulates PCM devices with careful attention to thermoelectric transport and the resulting impact on programming current during the reset operation. The electrothermal simulations consider Thomson heating within the phase-change material and Peltier heating at the electrode interface. Using representative values for the Thomson and Seebeck coefficients extracted from our past measurements of these properties, we predict a cell temperature increase of 44% and a decrease in the programming current of 16%. Scaling arguments indicate that the impact of thermoelectric phenomena becomes greater with smaller dimensions due to enhanced thermal confinement. This work estimates the scaling of this reduction in programming current as electrode contact areas are reduced down to 10 nm × 10 nm. Precise understanding of thermoelectric phenomena and their impact on device performance is a critical part of PCM design strategies.

Evaluating Broader Impacts of Nanoscale Thermal Transport Research

“…The thermal transport properties identified in the past studies allow complex device simulations accounting for phase impurities [133], thermal boundary resistance [137], and thermoelectric heating effects [138]. Precise knowledge of thermal transport phenomena and the resulting distributions of temperature, electric field, and current density have made important contributions to the improvement of existing designs and the discovery of breakthrough geometries.…”

Size-dependent chemical transformation, structural phase change, and optical properties of nanowires

“…The aforementioned studies on size-dependent electrical switching in nanowires suggest the geometrical importance of phase-change materials for continued size scaling towards obtaining high density memory devices with low power consumption[153-157]. Further development of novel nanomaterials in unconventional geometries offers opportunities to investigate the ultimate size limit of the electrically-driven phase change at the nanometer scale.…”

Ab initio description of the thermoelectric properties of heterostructures in the diffusive limit of transport

“…Nevertheless, beside the need of sophisticated techniques to measure , knowledge and controlling of the Thomson coefficient could, e.g., lead to a significant reduction of the programming current in phase‐change memory devices (). Moreover, a large in a broad temperature range could lead to a new kind of thermoelectric coolers based on the Thomson effect.…”