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Characterization of Cr‐doped Sb 2 Te 3 films and their application to phase‐change memory
Author(s) -
Wang Qing,
Liu Bo,
Xia Yangyang,
Zheng Yonghui,
Huo Ruru,
Zhu Min,
Song Sannian,
Lv Shilong,
Cheng Yan,
Song Zhitang,
Feng Songlin
Publication year - 2015
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201510214
Subject(s) - phase change memory , materials science , thermal stability , amorphous solid , phase change material , doping , crystallization , phase (matter) , analytical chemistry (journal) , thermal , chemical engineering , optoelectronics , nanotechnology , crystallography , thermodynamics , chemistry , physics , organic chemistry , layer (electronics) , chromatography , engineering
Phase‐change memory (PCM) is regarded as one of the most promising candidates for the next‐generation nonvolatile memory. Its storage medium, phase‐change material, has attracted continuous exploration. Along the traditional GeTe–Sb 2 Te 3 tie line, the binary compound Sb 2 Te 3 is a high‐speed phase‐change material matrix. However, the low crystallization temperature prevents its practical application in PCM. Here, Cr is doped into Sb 2 Te 3 , called Cr–Sb 2 Te 3 (CST), to improve the thermal stability. We find that, with increase of the Cr concentration, grains are obviously refined. However, all the CST films exhibit a single hexagonal phase as Sb 2 Te 3 without phase separation. Also, the Cr helps to inhibit oxidation of Sb atoms. For the selected film CST_10.5, the resistance ratio between amorphous and crystalline states is more than two orders of magnitude; the temperature for 10‐year data retention is 120.8 °C, which indicates better thermal stability than GST and pure Sb 2 Te 3 . PCM cells based on CST_10.5 present small threshold current/voltage (4 μA/0.67 V). In addition, the cell can be operated by a low SET/RESET voltage pulse (1.1 V/2.4 V) with 50 ns width. Thus, Cr–Sb 2 Te 3 with suitable composition is a promising novel phase‐change material used for PCM with high speed and good thermal stability performances. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)