Electrical Characteristics of Si0.8Ge0.2 p-MOSFET With TMA Pre-Doping and NH3 Plasma IL Treatment

We successfully fabricated p-MOSFETs on Si
_0.8
Ge
_0.2
substrate using trimethylaluminum (TMA) pre-doping and NH
₃
plasma as interfacial layer (IL) treatment for HfO
₂
-based gate stacks. X-ray photoelectron spectroscopy (XPS) findings indicated that SiGe interface with TMA pre-doping and NH
₃
plasma was free from Ge–O bonds and mainly composed of Si–N and Al–O bonds. With this IL treatment, p-MOSFET revealed an improved subthreshold swing of 98 mV/decade and a high
${I}_{ \mathrm{ON}} / {I}_{ \mathrm{OFF}}$
ratio of
$6\times 10^{{6}}$
. Furthermore, the
${I}_{D}$
–
${V}_{D}$
curves of p-MOSFET showed that the driving current was enhanced from 0.5 to
$1.8~\mu \text{A} / \mu \text{m}$
at
${V}_{D} = -1$
V. Therefore, the proposed scheme is a simple technique to achieve a high-quality interface on a SiGe substrate.