Comparative investigation into the interface passivation of Ge n- and p-MOSFETs with various 2D materials

2D materials provide an alternative way to passivate the Ge/oxide interface because of their conduction and valence band offsets. The effectiveness of their interface passivation is examined by evaluating the carriers' population in the channel of 2D passivated Ge n- and p-metal-oxide-semiconductor field-effect transistor (MOSFETs). The bilayer MoS2 interfacial passivation layer reduces both surface roughness and phonon scattering, which provides a performance boost. Monolayer MoSe2, WS2, MoS2, and black phosphorus, as well as bilayer MoS2 and WS2, can realize effective interface passivation for both Ge n- and p-MOSFETs. The carriers can penetrate 2D material if there are more than two 2D layers. (C) 2019 The Japan Society of Applied Physics.