Excellent data retention characteristic of Te-based conductive-bridge RAM using semiconducting Te filament for storage class memory

• Published in: Solid-state electronics Vol. 153; pp. 8 - 11
• Main Authors: Lee, Sangmin, Song, Jeonghwan, Lim, Seokjae, Chekol, Solomon Amsalu, Hwang, Hyunsang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2019
• Subjects: Activation energy; Conductive-bridge RAM (CBRAM); Retention; Retention; Activation energy; Conductive-bridge RAM (CBRAM)
• ISSN: 0038-1101; 1879-2405
• DOI: 10.1016/j.sse.2018.12.008

•The virgin resistance and forming voltage are decreased with increasing Zr composition in ZrxTe1−x (0.5 ≦ x ≦ 0.7) and decreasing electrolyte thickness.•The temperature-dependent resistance of the formed CF in Te-based CBRAM shows semiconducting behavior and a gradual change of conductance lower than 1.0 G0 in the erase step.•Activation energy for the out-diffusion of Te atoms does not contribute significantly to the excellent retention characteristics of Te-CBRAM. In this work, we explore the electrical properties and data retention of Te-based conductive-bridge random-access memory (CBRAM) of ZrxTe1−x/Al2O3/Pt cells. The virgin resistance and forming voltage are decreased with increasing Zr composition (0.5 ≦ x ≦ 0.7) and decreasing electrolyte thickness. The resistance of the conductive filament (CF) formed in the Te-CBRAM shows semiconducting behavior that is decreased with increasing temperature, whereas a Cu-based CBRAM shows metallic behavior. Furthermore, the conductance change of Te-based CBRAM, during the filament dissolution step, occurs with lower conductance units than those of Cu/Ag-based CBRAM. The most differentiable characteristics of both devices are the data retention. Te-based CBRAM shows better data stability at high temperature (150 °C) than Cu-based device. Accelerated tests (250, 270, and 300 °C) were performed to understand the data retention of the Te-CBRAM, yielding excellent retention characteristics (10 years at 177 °C) despite its relatively low activation energy (Ea, 1.07 eV) than Cu/Ag- based devices. We believe that the excellent retention properties of Te-based devices are more influenced by the wide effective CF size than by Ea.