Interfacial layer-free ZrO2 on Ge with 0.39-nm EOT, κ∼43, ∼2×10−3 A/cm2 gate leakage, SS =85 mV/dec, Ion/Ioff =6×105, and high strain response

0.39-nm ultrathin EOT ZrO
2
having κ value as high as ∼43 without an interfacial layer (IL) is demonstrated on Ge substrates. The EOT and gate leakage are much lower than the recent reported data [1]. In situ NH
3
/H
2
remote plasma treatment (RPT) after RTO-grown ultrathin (<1nm) GeO
2
/Ge and prior to PEALD ZrO
2
leads to the formation of tetragonal phase ZrO
2
and the inhibition of GeO
x
IL regrowth. As the number of RPT cycles increases, it is observed that not only higher [N] but more GeO
2
component formed on Ge surface. GeO diffuses into ZrO
2
layer via the interface reaction (Ge+GeO
2
→ 2GeO) and stabilize the tetragonal phase ZrO
2
. The gate dielectric has a leakage current ∼10
⁴
X lower than other reported dielectrics in this EOT region. Ge (001) pMOSFET has low SS of 85 mV/dec and high I
on
/I
off
of ∼6×10
⁵
at V
d
= −1V, while nMOSFET has SS of 90 mV/dec and I
on
/I
off
of ∼1×10
⁵
at V
d
=1V. The peak electron mobility is determined by the remote phonon scattering stemming from the high-κ value. The biaxial tensile strain of ∼0.04% applied on Ge (111) nMOSFET with an EOT=0.78nm produces a 4.8% drain current enhancement along the <110> channel.