Negative Capacitance Black Phosphorus Transistors With Low SS

Negative capacitance (NC) shows great potential to enable transistors with the steeper slope, which is very useful for voltage/power applications. Black phosphorus (BP) is theoretically predicted as good channel materials for NC-FETs. However, the experimental demonstration of BP has so far remained elusive. Here, for the first time, NC transistors based on BP have been demonstrated. By connecting to a 20-nm HfZrO ferroelectric capacitor, both two types of BP transistors show lower subthreshold slope (SS). For 5-nm AlO
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BP transistor, the SS decreases from 200 to 104 mV/dec. The experimental results are analyzed with the BP-NCFET model, and the calculated transfer curve can fit well with the experimental curve, which proves the validation of the model. Our work sheds light on using NC BP FETs for low-power flexible electronics applications.