Review on remote phonon scattering in transistors with metal-oxide-semiconductor structures adopting high-k gate dielectrics

Abstract

One main obstacle to obtaining high carrier mobility in transistors with metal-oxide-semiconductor (MOS) structures is carrier scattering, which has been systematically investigated. In the past few decades, much attention was preferentially paid to the scatterings arising from the region near the semiconductor/oxide interface because they can affect the carrier transport in the semiconductor channel more directly and effectively, e.g., polaronic effect, Coulomb scattering, surface-roughness scattering, and intrinsic phonon scattering resulted from the thermal vibration of the semiconductor channel. However, scattering originated from hybrid interface plasmon/optical-phonon excitations, so-called remote phonon scattering, has been neglected to some extent, but is especially severe for gate oxides with high dielectric constants due to the easy vibrations of their atoms. On the other hand, plasmons generated from the oscillations of majority carriers in the gate electrode can couple with the remote phonons to suppress the remote phonon scattering, which is called the gate screening effect. However, when the frequency of the gate-electrode plasmon is close/equal to that of the gate-dielectric phonon, the resonance between the gate electrode and the gate dielectric greatly enhances the remote phonon scattering to severely degrade the carrier mobility (so-called gate antiscreening effect). This work intends to give a comprehensive review on the origins, effects, suppression methods, and recent advances of the remote phonon scattering, with a view to achieving high-mobility MOS devices (including those based on two-dimensional semiconductors) with high-k gate dielectrics for future high-speed electronic applications.