Analysis of quasi-ballistic hole transport capability of Ge and Si nanowire pMOSFETs by a quantum-corrected Boltzmann transport equation

The quasi-ballistic hole transport capabilities of Ge and Si nanowire pMOSFETs were analyzed based on a quantum- corrected Boltzmann transport equation. A new formalism of quantum-correction potential was proposed, and using this model, the current drive capabilities of Ge and Si nanowire pMOSFETs were compared. Though the ON-current was larger in the Ge nanowire pMOSFET, the transmission coefficients are similar between Ge and Si, because the higher hole mobility of Ge is canceled by its slower energy relaxation. Thus, the larger current of the Ge nanowire pMOSFET was attributed to its larger injection current. The impact of device geometry on the performance was also investigated, and the [110]-oriented Ge nanowire pMOSFET with a 15 nm gate length exhibited the highest performance among the devices considered in this study.