Hysteretic switching with a sub-
kT/q steep slope (13 mV/decade at room temperature) is experimentally demonstrated in MOSFETs with PbZr
0.52 Ti
0.48O
3 as a ferroelectric (FE) gate insulator, integrated on a silicon channel with a nonperovskite high-
k dielectric (HfO
2) as a buffer interlayer. The steep switching is independent of drain bias. For the first time, sub-
kT/q switching due to FE negative capacitance is observed not at low currents, but in strong inversion (
100
). Steep switching in strong inversion provides an important point of consistency with the predictions of the Landau–Devonshire theory and the Landau–Khalatnikov equation.