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.

Improved subthreshold swing of MoS2 negative-capacitance transistor by fluorine-plasma treatment on ferroelectric Hf0.5Zr0.5O2 gate dielectric

“…Clearly, the Zr 3d and Hf 4f peaks of the plasma-treated Hf 0.5 Zr 0.5 O 2 film are shifted to lower BE's (182.5 eV and 16.2 eV respectively) relative to those of the untreated Hf 0.5 Zr 0.5 O 2 film (183.1 eV and 16.4 eV respectively), implying a reduction of oxygen vacancies. This is beneficial to mitigating the depolarization field at the interface between Hf 0.5 Zr 0.5 O 2 and Al 2 O 3 , thus increasing the amplification effect on the surface potential of the MoS 2 channel during the NC operation in addition to reducing gate leakage path [31,32].…”

Performance optimization of GaAs NCFET with a complex oxide ferroelectric gate ​

“…Though much research has been done on NCFET [12][13][14][15][16], while investigations on NCFET based on GaAs substrate are still limited, much uncertainty still exists. For NCFET based on Silicon, it has been found that: (1) When channel length (LC) is increased, the gate voltage amplification (GVA) effect is weakened [17].…”