Reliability Impact of Chalcogenide-Structure Relaxation in Phase-Change Memory (PCM) Cells—Part I: Experimental Study

Author

Ielmini, Daniele ; Sharma, Deepak ; Lavizzari, Simone ; Lacaita, Andrea L.

Author_Institution

Dipt. di Elettron. e Inf., Politec. di Milano, Milan

Volume

56

Issue

5

fYear

2009

fDate

5/1/2009 12:00:00 AM

Firstpage

1070

Lastpage

1077

Abstract

The phase-change memory (PCM) relies on the electrical properties of the chalcogenide materials to represent the stored bit of information. As a result, data stability depends on structural relaxation (SR) in the amorphous chalcogenide phase, which results in a temperature-accelerated time evolution of the electrical properties of the active material. Here, we address the time, temperature, and bias dependence of SR effects on the amorphous Ge₂Sb₂Te₅ (GST) material used in PCM cells. Electrical measurements for increasing annealing time and temperature indicate that SR can be described by a defect annihilation process in the amorphous chalcogenide material. Finally, the stability of chalcogenide resistance as a function of the read conditions is discussed, for the purpose of reducing the impact of SR on the reliability of PCM devices.

Keywords

chalcogenide glasses; phase change memories; active material; amorphous chalcogenide phase; annihilation process; chalcogenide-structure relaxation; electrical properties; phase-change memory cells; Amorphous materials; Electric variables measurement; Electrical resistance measurement; Phase change materials; Phase change memory; Stability; Strontium; Tellurium; Temperature dependence; Time measurement; Amorphous semiconductors; chalcogenide materials; nonvolatile memory; phase-change memory (PCM); reliability estimation; reliability modeling;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/TED.2009.2016397

Filename

4804709