Black Phosphorus Transistors with Enhanced Hole Transport and Subthreshold Swing using Ultra-Thin HfO2 High-k Gate Dielectric

We report the realization of high performance BP transistors integrated with an ultra-thin HfO2 high-k gate dielectric using a low temperature CMOS process. The fabricated devices were shown to demonstrate an enhanced hole mobility of > 400 cm(2)/Vs and subthreshold swing (SS) of similar to 69 mV/dec at room temperature. These figure-of-merits are benchmarked to be the best-of-its-kind, which outperform previously reported BP transistors realized on traditional SiO2 gate dielectric. X-ray photoelectron spectroscopy analysis further reveals the evidence of a more chemically stable BP interface when formed on HfO2 high-k as opposed to SiO2, which gives rise to a lower interface states density that accounts for the SS and hole mobility improvement. These results unveil the potential of BP as a new channel material for future nanoelectronics applications.