Comprehensive Understanding of the Mobility Scattering Mechanisms and Evaluation of the Universal Mobility in Ultra-Thin-Body Ge-OI p- and n-MOSFETs

Abstract

The mobility scattering mechanisms in the ultra-thin-body (UTB) Ge-OI p- and n-MOSFETs have been systematically investigated. It is found that the ${E} _{\text {eff}}^{-{2}}$ dependence is confirmed for the hole mobility in Ge-OI pMOSFETs, while the electron mobility exhibits an unusually strong dependence on ${E} _{\text {eff}}$ ( $\propto {E} _{\text {eff}}^{-{4}}\text {)}$ . The $\mu _{\text {ph}}$ exhibits an ${E} _{\text {eff}}^{\,{-{0}.{3}}}$ dependence for both holes and electrons, along with a temperature dependence of $\sim {T} ^{\,{-{1}.{8}}}$ . The $\mu _{\text {total}}$ is measured at different depletion layer carrier densities ( ${N} _{\text {depl}}\text {)}$ , revealing that $\mu _{\text {Coulomb}}$ increases with the rise of ${N} _{\text {depl}}$ . Specially, $\mu _{\text {Coulomb}}$ exhibits ${N} _{\text {depl}}^{{0}.{5}}$ and ${N} _{\text {depl}}^{{1}.{8}}$ dependencies for electrons and holes, respectively. Consequently, more pronounced mobility degradation has been confirmed in UTB Ge-OI nMOSFETs than in UTB Ge-OI pMOSFETs. These findings suggest universal carrier scattering mechanisms for both holes and electrons in UTB Ge-OI channels, which are valuable for understanding carrier transport in thin-channel Ge devices for future advanced technology nodes.