We successfully fabricated p-MOSFETs on Si0.8Ge0.2 substrate using trimethylaluminum (TMA) pre-doping and NH3 plasma as interfacial layer (IL) treatment for HfO2-based gate stacks. X-ray photoelectron spectroscopy (XPS) findings indicated that SiGe interface with TMA pre-doping and NH3 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 ION/IOFF ratio of 6×106. Furthermore, the ID - VD curves of p-MOSFET showed that the driving current was enhanced from 0.5 to 1.8μA/μm at VD = -1 V. Therefore, the proposed scheme is a simple technique to achieve a high-quality interface on a SiGe substrate.
- Interface passivation
- remote plasma nitridation
- SiGe channel
- trimethylaluminum (TMA) pre-doping