The so-called Boltzmann tyranny defines the fundamental thermionic limit of the subthreshold slope of a metal–oxide–semiconductor field-effect transistor (MOSFET) at 60 mV dec−1 at room temperature and therefore precludes lowering of the supply voltage and overall power consumption1,2. Adding a ferroelectric negative capacitor to the gate stack of a MOSFET may offer a promising solution to bypassing this fundamental barrier3. Meanwhile, two-dimensional semiconductors such as atomically thin transition-metal dichalcogenides, due to their low dielectric constant and ease of integration into a junctionless transistor topology, offer enhanced electrostatic control of the channel4,5,6,7,8,9,10,11,12. Here, we combine these two advantages and demonstrate a molybdenum disulfide (MoS2) two-dimensional steep-slope transistor with a ferroelectric hafnium zirconium oxide layer in the gate dielectric stack. This device exhibits excellent performance in both on and off states, with a maximum drain current of 510 μA μm−1 and a sub-thermionic subthreshold slope, and is essentially hysteresis-free. Negative differential resistance was observed at room temperature in the MoS2 negative-capacitance FETs as the result of negative capacitance due to the negative drain-induced barrier lowering. A high on-current-induced self-heating effect was also observed and studied.
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This material is based upon work partly supported by the Air Force Office of Scientific Research (AFOSR)/National Science Foundation (NSF) Two-Dimensional Atomic-layer Research and Engineering (2DARE) programme, Army Research Office (ARO) and Semiconductor Research Corporation (SRC).
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The authors declare no competing financial interests.
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Si, M., Su, CJ., Jiang, C. et al. Steep-slope hysteresis-free negative capacitance MoS2 transistors. Nature Nanotech 13, 24–28 (2018). https://doi.org/10.1038/s41565-017-0010-1
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