Improved Negative-Capacitance Switch of Ferroelectric Field Effect Transistor Using Defect Passivation Engineering

Abstract

A ferroelectric negative-capacitance (NC) transistor using aluminum-doped hafnium oxide (HfAlOx) with fluorine passivation is successfully demonstrated. The fluorine-passivated device shows a nearly hysteresis-free forward/reverse swing of sub-30 mV dec−1 for symmetric switch, a wide sub-60 mV (dec·swing)−1 range over 4 decades of drain current, an ultralow off-leakage current of 4 fA μm−1, and a high on/off current ratio of >108. The fluorine defect passivation (FP) reduces oxygen vacancies of ferroelectric HfAlOx to mitigate interface depolarization field and thereby reinforce surface potential amplification effect during NC operation.