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 HfO
2
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 ∼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 SiO
2
gate dielectric. X-ray photoelectron spectroscopy analysis further reveals the evidence of a more chemically stable BP interface when formed on HfO
2
high-k as opposed to SiO
2
, 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.