Few-layer black phosporous PMOSFETs with BN/AI2O3 bilayer gate dielectric: Achieving Ion=850μA/μm, gm=340μS/μm, and Rc=0.58kΩ·μm

In this paper, high-performance few-layer black phosphorus (BP) PMOSFETs have been demonstrated by using MOCVD BN and ALD Al
2
O
3
as the top-gate dielectric as well as the passivation layer. Highest Ion of 850μA/μm (V
ds
= −1.8 V) and g
m
of 340μS/μm (Vds = −0.8 V) have been achieved with the 200nm chancel length (L
ch
) devices. Record low contact resistance (R
c
) of 0.58kΩ·μm has been obtained on BP transistors by contact engineering. The gate leakage of the BN/Al
2
O
3
bilayer gate dielectric is less than 10
⁻¹²
A/μm
²
(V
g
= −1V) with an EOT of 3nm. SS and hysteresis voltage as low as 70mV/dec and 0.1V have been achieved, indicating a high quality interface between BP and BN.