Superior High Transistor’s Effective Mobility of 325 cm(2)/V-s by 5 nm Quasi-Two-Dimensional SnON nFET

This work reports the first nanocrystalline SnON (7.6% nitrogen content) nanosheet n-type Field-Effect Transistor (nFET) with the transistor’s effective mobility (µ(eff)) as high as 357 and 325 cm(2)/V-s at electron density (Q(e)) of 5 × 10(12) cm(−2) and an ultra-thin body thickness (T(body)) of 7 nm and 5 nm, respectively. At the same T(body) and Q(e), these µ(eff) values are significantly higher than those of single-crystalline Si, InGaAs, thin-body Si-on-Insulator (SOI), two-dimensional (2D) MoS(2) and WS(2). The new discovery of a slower µ(eff) decay rate at high Q(e) than that of the SiO(2)/bulk-Si universal curve was found, owing to a one order of magnitude lower effective field (E(eff)) by more than 10 times higher dielectric constant (κ) in the channel material, which keeps the electron wave-function away from the gate-oxide/semiconductor interface and lowers the gate-oxide surface scattering. In addition, the high µ(eff) is also due to the overlapped large radius s-orbitals, low 0.29 m(o) effective mass (m(e)*) and low polar optical phonon scattering. SnON nFETs with record-breaking µ(eff) and quasi-2D thickness enable a potential monolithic three-dimensional (3D) integrated circuit (IC) and embedded memory for 3D biological brain-mimicking structures.