  In this work, we demonstrate the enlargement of the memory window of Si
channel FeFET with ferroelectric Hf0.5Zr0.5O2 by gate-side dielectric
interlayer engineering. By inserting an Al2O3 dielectric interlayer between TiN
gate metal and ferroelectric Hf0.5Zr0.5O2, we achieve a memory window of 3.2 V
with endurance of ~105 cycles and retention over 10 years. The physical origin
of memory window enlargement is clarified to be charge trapping at the
Al2O3/Hf0.5Zr0.5O2 interface, which has an opposite charge polarity to the
trapped charges at the Hf0.5Zr0.5O2/SiOx interface.
