Strain-based room-temperature non-volatile MoTe2 ferroelectric phase change transistor

• Published in: Nature nanotechnology Vol. 14; no. 7; pp. 668 - 673
• Main Authors: Hou, Wenhui, Azizimanesh, Ahmad, Sewaket, Arfan, Peña, Tara, Watson, Carla, Liu, Ming, Askari, Hesam, Wu, Stephen M.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.07.2019; Nature Publishing Group
• Subjects: 140/133; 639/166/987; 639/301/119/996; 639/766/1130; 639/766/119/2795; 639/925/927/1007; Chemistry and Materials Science; Computation; Computer applications; Conductivity; Current leakage; Electric fields; Ferroelectric materials; Ferroelectricity; Field effect transistors; Landscape architecture; Letter; Materials Science; Molybdenum compounds; Nanotechnology; Nanotechnology and Microengineering; Phase transitions; Power consumption; Room temperature; Semiconductor devices; Switching; Tellurides; Thin films; Transistors; Transition metal compounds; Volatility
• DOI: 10.1038/s41565-019-0466-2
• ISSN: 1748-3387; 1748-3395

The primary mechanism of operation of almost all transistors today relies on the electric-field effect in a semiconducting channel to tune its conductivity from the conducting ‘on’ state to a non-conducting ‘off’ state. As transistors continue to scale down to increase computational performance, physical limitations from nanoscale field-effect operation begin to cause undesirable current leakage, which is detrimental to the continued advancement of computing 1 , 2 . Using a fundamentally different mechanism of operation, we show that through nanoscale strain engineering with thin films and ferroelectrics the transition metal dichalcogenide MoTe 2 can be reversibly switched with electric-field-induced strain between the 1T′-MoTe 2 (semimetallic) phase to a semiconducting MoTe 2 phase in a field-effect transistor geometry. This alternative mechanism for transistor switching sidesteps all the static and dynamic power consumption problems in conventional field-effect transistors 3 , 4 . Using strain, we achieve large non-volatile changes in channel conductivity ( G on / G off  ≈ 10 7 versus G on / G off  ≈ 0.04 in the control device) at room temperature. Ferroelectric devices offer the potential to reach sub-nanosecond non-volatile strain switching at the attojoule/bit level 5 – 7 , with immediate applications in ultrafast low-power non-volatile logic and memory 8 while also transforming the landscape of computational architectures because conventional power, speed and volatility considerations for microelectronics may no longer exist. Strain-induced phase change in MoTe 2 enables reversible channel conductivity switching in a field-effect transistor geometry.