Electrical Characteristics of Si $_{{0.8}}$ Ge $_{{0.2}}$ p-MOSFET With TMA Pre-Doping and NH $_{{3}}$ 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 $I_{{on}}$ / $I_{{off}}$ ratio of 6 x 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 A/mu m at $V_{D} = -$ 1 V. Therefore, the proposed scheme is a simple technique to achieve a high-quality interface on a SiGe substrate.