2023 Fiscal Year Final Research Report

Improvement of crystallization temperature by controlling crystal distortion of phase change material GeTe by doping transition metal elements

Research Project

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Project/Area Number	20K04568
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 21050:Electric and electronic materials-related
Research Institution	Ube National College of Technology
Principal Investigator	Senba Shinya 宇部工業高等専門学校, 電気工学科, 教授 (40342555)
Co-Investigator(Kenkyū-buntansha)	浅田裕法山口大学, 大学院創成科学研究科, 教授 (70201887) 佐藤仁広島大学, 放射光科学研究センター, 准教授 (90243550)
Project Period (FY)	2020-04-01 – 2024-03-31
Keywords	相変化メモリ / 相変化材料 / 結晶化温度
Outline of Final Research Achievements	Phase-change random access memory (PCRAM) is a next-generation nonvolatile memory that distinguishes between a low-resistance crystalline phase and a high-resistance amorphous phase and controls their states by pulse switching. To improve the thermal endurance of PCRAM, there is a challenge to increase the crystallization temperature. In this study, we decided to improve the crystallization temperature by doping Mn into GeTe, a phase-change material. First, samples of GeTe and Ge1-xMnxTe thin films were prepared by vacuum evaporation. Then, to clarify the crystallization temperature of the samples, the resistance values were measured while the fabricated samples were heated to 300 deg. The crystalline state of the samples was evaluated using X-ray diffraction. The elemental content of the samples was determined using energy dispersive X-ray analysis to determine the Mn concentration. The results showed that the crystallization temperature increased with increasing Mn concentration.
Free Research Field	物性科学、電子材料、薄膜
Academic Significance and Societal Importance of the Research Achievements	未だ実用化されていない相変化メモリ（PCRAM）は、不揮発かつ高速なメモリとして期待されているが、熱耐性が低いという課題が残されている。熱耐性を向上するためには材料固有の結晶化温度を高める必要がある。本研究はその結晶化温度の高い相変化材料を開発するものであり、その成果はPCRAMの実用化を進展させるうえで社会的意義がある。 ※相変化メモリとは結晶相とアモルファス相をデータに対応付けたメモリで、電源を切ってもデータが残る不揮発性を特徴とした次世代メモリとして注目されている。