Title :
Grain Boundaries, Phase Impurities, and Anisotropic Thermal Conduction in Phase-Change Memory
Author :
Li, Zijian ; Lee, Jaeho ; Reifenberg, John P. ; Asheghi, Mehdi ; Jeyasingh, Rakesh G D ; Wong, H. S Philip ; Goodson, Kenneth E.
Author_Institution :
Mech. Eng. Dept., Stanford Univ., Stanford, CA, USA
fDate :
7/1/2011 12:00:00 AM
Abstract :
Thermal conduction strongly influences the programming energy and speed in phase-change-memory devices. The thermal conductivity of the crystalline phase of Ge2Sb2 Te5 can be strongly anisotropic due to phase impurities at grain boundaries. This letter models this effect using effective medium arguments, lends further support to the hypothesis that phase impurities are responsible for the anisotropy, and estimates the impact of anisotropic heat conduction on device performance. Electrothermal simulations predict that the reduced in-plane conductivity will allow closer spacing of lateral-cell devices and reduce the reset programming current by 20%-30%.
Keywords :
antimony compounds; germanium compounds; grain boundaries; heat conduction; phase change memories; thermal conductivity; Ge2Sb2Te5; anisotropic heat conduction; anisotropic thermal conduction; crystalline phase; electrothermal simulation; grain boundary; phase impurity; phase-change-memory device; Anisotropic magnetoresistance; Conductivity; Grain size; Phase change materials; Phase change memory; Programming; Thermal conductivity; Chalcogenide; nonvolatile memories; phase-change memory (PCM); thermal conductivity anisotropy;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2011.2150193
