High thermal stability and fast operation speed phase-change memory devices containing Hf-doped Ge2Sb2Te5 films

• Published in: Materials letters Vol. 278; p. 128402
• Main Authors: Wang, Ruobing, Shen, Jiabin, Chen, Xin, Wang, Hao, Song, Sannian, Song, Zhitang
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2020; Elsevier BV
• Subjects: Crystallization; Doping; Electrical properties; Grain size; Hafnium; Materials science; Memory devices; Nanocomposites; Phase-change memory; Thermal stability; Thermodynamic properties; Electrical properties; Nanocomposites; Phase-change memory; Thermal stability; Hafnium
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2020.128402

•The increase of Hafnium content enhances the thermal stability of Ge2Sb2Te5.•Hafnium dopants suppress the process of crystallization.•Hafnium dopants reduce the size of faced-centered cubic phase Ge2Sb2Te5 grains.•Hafnium-doped Ge2Sb2Te5 phase-change memory device has fast operation speed and good endurance. Ge2Sb2Te5 (GST) materials have been widely investigated for applying in phase-change memory (PCM). However, the low amorphous thermal properties limit its application in high-density memory devices, thus doping modified has been the subject of extensive studies in past decades. In this work, the amorphous thermal stability of GST can be significantly improved by doping hafnium elements without reducing operation speed. A higher crystallization temperature (~221 °C) and 10-year data retention temperature (~114 °C) are achieved in Hf0.04(Ge2Sb2Te5)0.96 alloy. The addition of Hf elements helps to suppress crystallization and decrease the grain size of rock-salt phase. Besides, the PCM cell based on Hf0.04(Ge2Sb2Te5)0.96 exhibits a faster operation speed (10 ns) than GST-based one and could be operated repeatedly for over 2́105 cycles, showing that Hf-doped GST is a promising material for PCM devices.