Evaluation of Quasi-Ballistic Transport Behaviors in Ge pMOSFETs With NiGe Metal Source/Drain

The quasi-ballistic transport characteristics in the Ge pMOSFETs with NiGe metal source/drain (S/D) are analyzed. It is found that the Ge pMOSFETs represent a remarkable velocity overshoot and the injection velocity of the hole achieves <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.8\times \,\, 10^{{7}}$ </tex-math></inline-formula> cm/s. Additionally, the Ge pMOSFETs with metal S/D exhibit a much smaller 1/Bsat than those in Ge-OI pMOSFETs with conventional ion implantation S/D. These phenomena are attributable to the improved lateral electrical field at the metal S/D edge. It is suggested that the metal S/D structure is an effective booster to increase the electrical performance of ballistic transport Ge pMOSFETs.