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.