Transconductance degradation in thin-Oxide MOSFET's

In this work we investigate the transconductance degradation effect which occurs in thin-oxide FET's due to finite inversion-layer capacitance and to the decrease of the electron mobility as the electric field increases. Capacitance measurements are performed at room and at liquid-nitrogen temperature on 10 nm oxide FET's, and the data compared with a classical and a quantum-mechanical model extended to take into account a non-uniform doping profile in the silicon substrate. Accurate mobility determinations are performed accounting for the non-uniform distribution of the mobile charge along the channel. Design trade-offs for submicron FET's are finally discussed.