Thickness Scaling and Roughness-Induced Mobility Cliff in Ultra-thin-body MOSFETs
Published in IEEE Electron Device Letters (IEEE EDL), 2026
For future technology generations, Ultra-thin-body (UTB) MOSFETs are expected to replace classical bulk MOSFETs owing to their superior electrostatic scaling. However, process-control variability, especially under cryogenic operation, has heightened concerns regarding the channel/gate oxide interface. In this regime, interface-induced surface-roughness (SR) scattering becomes increasingly dominant, leading to a sharp roll-off in mobility. In this paper, we present (i) a universal thickness-scaling principle for long-channel mobility (μc), validated across multiple transistor technologies, that captures the non-ideal mobility roll-off exponent (neff ) by explicitly accounting for finite potential-well type and confinement, and (ii) a closed-form analytical model that directly extracts the critical thickness (Tcrit) and the associated critical-mobility trade-off. Overall, this compact and scalable approach quantitatively highlights the need for stringent thickness uniformity to preserve mobility control in next-generation complementary field-effect transistors (CFETs) technology.
Mir Md Fahimul Islam, In Huh, …, et al., IEEE Electron Device Letters (IEEE EDL), 2026