Performance Improvement of GeTex-Based Ovonic Threshold Switching Selector by C Doping

• Published in: IEEE electron device letters Vol. 42; no. 5; pp. 688 - 691
• Main Authors: Wang, Lun, Cai, Wang, He, Da, Lin, Qi, Wan, Daixing, Tong, Hao, Miao, Xiangshui
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.05.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 1S1R; Doping; First principles; high-density memory array; Leakage currents; Ovonic threshold switching (OTS); Performance evaluation; Phase change materials; selector; Switches; Threshold voltage; Voltage measurement
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2021.3064857

In this letter, we fabricated a C-doped GeTe x Ovonic threshold switching (OTS) selector in a via-hole structure. The material composition is simple without toxic element doping. Performance of the GeTe x -based selector is improved to be comparable to commercial GeSe-based selectors through C doping. A selector with advantages of low off-current (2 nA), low threshold voltage (1.26 V) accompanying with a big voltage window (0.55 V), high selectivity (<inline-formula> <tex-math notation="LaTeX">> 4.2\times 10 ^{4} </tex-math></inline-formula>), satisfactory endurance (> 10 7 cycles with 2 mA on-current), low cycle-to-cycle <inline-formula> <tex-math notation="LaTeX">\text{V}_{{\mathrm {th}}} </tex-math></inline-formula> variation and fast operating speed (8.5 ns) was fabricated. Besides, selector with self-limited on-current character was found. Next, reasons behind off-current reduction and consistency improvement by using C doping were studied by First-principles calculations.