High-mobility germanium p-MOSFETs by using HCl and (NH₄)₂S surface passivation

To achieve a high-quality high-κ/Ge interfaces for high hole mobility Ge p-MOSFET applications, a simple chemical cleaning and surface passivation scheme is introduced, and Ge p-MOSFETs with effective channel hole mobility up to 665 cm²/V·s are demonstrated on a Ge (111) substrate. Moreover, a physical model is proposed to explain the dipole layer formation at the metal-oxide-semiconductor (MOS) interface by analyzing the electrical characteristics of HCl-and (NH₄)₂S-passivated samples.