[16p-C32-1~12] 16.1 Fundamental properties, evaluation, process and devices in disordered materials

3:15 PM - 3:30 PM JST(6:15 AM - 6:30 AM UTC)English Presentation

[16p-C32-8] Phase Change Memory Applications of Low-Melting 2D Van der Waals Transition-Metal Chalcogenide NbTe₄

〇Yi Shuang¹, Qian Chen^1,5, Mihyeon Kim², Yinli Wang², Yuta Saito^2,3, Shogo Hatayama³, Paul Fons⁴, Daisuke Ando², Momoji Kubo⁵, Yuji Sutou^1,2 (1.Tohoku Univ. (AIMR), 2.Tohoku Univ, (Eng), 3.AIST, 4.Keio Univ., 5.Tohoku Univ. (IMR))

Keywords:

2D-vdW,Transition metal chalcogenides,phase change memory

Two-dimensional (2D) van der Waals (vdW) transition metal dichalcogenides (TMDs) such as MoTe₂, have garnered significant attention in the realm of nonvolatile memory (NVM) due to their versatile electrical properties, scalability, and potential for phase manipulation. These materials offer promising avenues for the development of next-generation memory devices. However, the intricate switching mechanisms and complex fabrication processes of TMDs pose substantial challenges for large-scale production, limiting their widespread application. Sputtering has emerged as a viable technique for fabricating expansive 2D vdW TMDs, offering a potential solution to some of these manufacturing challenges. Nevertheless, the high melting points (T_m > 1000 °C) of conventional TMDs necessitate the use of elevated temperatures to achieve the desired crystalline quality, complicating the fabrication process and increasing energy consumption. In this study, we turn our focus to low-melting 2D vdW transition metal tetra-chalcogenides (TMTs), which present a promising alternative. Among these, NbTe₄ stands out as an ideal candidate due to its exceptionally low melting point of approximately 447 °C (onset temperature). This significantly lower melting point compared to traditional TMDs facilitates easier processing and lower energy requirements. Initially, as-deposited NbTe₄ exists in an amorphous phase. Through annealing at temperatures exceeding 272 °C, this amorphous phase can be transformed into a crystalline state. This unique combination of a low melting point and a high crystallization temperature (T_c) effectively addresses several critical challenges currently faced by phase-change material (PCM) compounds. Specifically, it helps mitigate issues related to high reset energies and the poor thermal stability of the amorphous phase, which are significant obstacles in the development of efficient and reliable PCM devices.