Phosphorus Deactivation and Electron Mobility Enhancement in Ultrathin Silicon Nanosheets

Ex-situ doping is used to introduce a constant dose (∼ 1\ rmx\ 1013\ cm-2) of P atoms into Si nanosheets with thickness ranging from 70 to 6 nm. Full activation of P atoms is demonstrated in Si nanosheets with thickness\ h\geq 30 nm. Conversely, progressive deactivation of dopant impurities is observed when decreasing the thickness of the Si nanosheets below 30 nm. Si nanosheets with thickness h < 10 nm exhibit electron mobility values higher than the ones reported for bulk Si at the same doping concentration. Data provide information for the design of ultra-scaled GAAFET devices.