Exploring and Suppressing Kink Effect of Black Phosphorus FieldEffect Transistors Operating in Saturation Regime

With continuous device scaling, avalanche breakdown in the two-dimensional (2D) transistors severely degrades device output characteristics and overall reliability. It is highly desirable to understand the origin of such electrical breakdown for exploring the high-performance 2D transistors. Here, we report an anomalous increase in drain currents of the black phosphorus (BP)-based transistors operating in saturation regime. Through the comprehensive investigation of various channel thicknesses, channel lengths and operating temperatures, it is attributed such novel behavior to the kink effect originating from impact ionization and related potential shift inside the channel, which is further confirmed by device numerical simulations. Furthermore, Nitrogen plasma treatment is carried out to eliminate the current anomalous increase and suppress the kink effect with improved saturation current. This work not only sheds light on the understanding of carrier transport within the BP transistor, but also could open up new potential for achieving high-performance and reliable electronic devices based on the 2D materials