Improved electrical and reliability characteristics in Ge p-MOSFETs with in-situ plasma treatments and capping Hf/Zr on interfacial layers

A Ge p-MOSFET with an ultralow equivalent oxide thickness (EOT) of ~0.47 nm and a high hole mobility of ~401 cm
²
/V-s is demonstrated in this work. The excellent electrical characteristics are obtained by in-situ H
₂
and NH
₃
plasma treatments on the Ge/High-K interface. The enhanced drive current can be attributed to the lower EOT or higher mobility. Device with a Hf cap layer demonstrates the lowest interface trap density and stress-induced leakage current. Moreover, device with Zr cap layer has the lowest hysteresis effects and stress-induced voltage shifts.