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

Volume

32

Issue

7

fYear

2011

fDate

7/1/2011 12:00:00 AM

Firstpage

961

Lastpage

963

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;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/LED.2011.2150193

Filename

5770177