Extremely High-κ Hf0.2Zr0.8O2 Gate Stacks Integrated Into Eight Stacked Ge0.95Si0.05 Nanowires and Nanosheets nFETs to Boost ION

By taking advantage of extremely high dielectric constant (
$\kappa $
) of 47, the Hf0.2Zr0.8O2 gate stacks are integrated into the eight stacked high mobility Ge0.95Si0.05 channels with low thermal budget (
$\leqq 450$
°C) to significantly enhance the
${I} _{ \mathrm{\scriptscriptstyle ON}}$
. Isotropic wet etching by
$\text{H}_{{2}}\text{O}_{{2}}$
and HNO3 serve well during the channel release of nanowires and nanosheets, respectively. The simulated
$\kappa $
versus Zr concentration in HZO can show that the
$\kappa $
can have a peak value at Zr concentration around 80%. The eight stacked Ge0.95Si0.05 nanowires and nanosheets with Hf0.2Zr0.8O2 gate stacks achieve the record high
${I} _{ \mathrm{\scriptscriptstyle ON}}$
per footprint of
$9200~\mu \text{A}$
and record high
${I} _{ \mathrm{\scriptscriptstyle ON}}$
per stack of
$360~\mu \text{A}$
at
${V} _{\text {OV}} ={V}_{\text {DS}}$
= 0.5 V, respectively, among all Si/GeSi/Ge 3-D nFETs. Moreover, the potential gate delay improvement by combining the extremely high-
$\kappa $
gate stacks and large floor number is studied by TCAD simulation using industrial device structures.